Showing 1–50 of 84 results for author: Scott, P

A Global Fit of Non-Relativistic Effective Dark Matter Operators Including Solar Neutrinos

Authors: Neal P. Avis Kozar, Pat Scott, Aaron C. Vincent

Abstract: We perform a global fit of dark matter interactions with nucleons using a non-relativistic effective operator description, considering both direct detection and neutrino data. We examine the impact of combining the direct detection experiments CDMSlite, CRESST-II, CRESST-III, DarkSide-50, LUX, LZ, PandaX-II, PandaX-4T, PICO-60, SIMPLE, SuperCDMS, XENON100, and XENON1T along with neutrino data from… ▽ More We perform a global fit of dark matter interactions with nucleons using a non-relativistic effective operator description, considering both direct detection and neutrino data. We examine the impact of combining the direct detection experiments CDMSlite, CRESST-II, CRESST-III, DarkSide-50, LUX, LZ, PandaX-II, PandaX-4T, PICO-60, SIMPLE, SuperCDMS, XENON100, and XENON1T along with neutrino data from IceCube and ANTARES. While current neutrino telescope data lead to increased sensitivity compared to underground nuclear scattering experiments for dark matter masses above 100 GeV, our future projections show that the next generation of underground experiments will significantly outpace solar searches for most dark matter-nucleon elastic scattering interactions. △ Less

Submitted 4 February, 2025; v1 submitted 23 October, 2023; originally announced October 2023.

Comments: 12+9 pages, 26 figures, Likelihoods available at https://zenodo.org/records/14641149. v2: matches the published version

Journal ref: JCAP 02 (2025) 007

Collider constraints on electroweakinos in the presence of a light gravitino

Authors: The GAMBIT Collaboration, Viktor Ananyev, Csaba Balázs, Ankit Beniwal, Lasse Lorentz Braseth, Andy Buckley, Jonathan Butterworth, Christopher Chang, Matthias Danninger, Andrew Fowlie, Tomás E. Gonzalo, Anders Kvellestad, Farvah Mahmoudi, Gregory D. Martinez, Markus T. Prim, Tomasz Procter, Are Raklev, Pat Scott, Patrick Stöcker, Jeriek Van den Abeele, Martin White, Yang Zhang

Abstract: Using the GAMBIT global fitting framework, we constrain the MSSM with an eV-scale gravitino as the lightest supersymmetric particle, and the six electroweakinos (neutralinos and charginos) as the only other light new states. We combine 15 ATLAS and 12 CMS searches at 13\,TeV, along with a large collection of ATLAS and CMS measurements of Standard Model signatures. This model, which we refer to as… ▽ More Using the GAMBIT global fitting framework, we constrain the MSSM with an eV-scale gravitino as the lightest supersymmetric particle, and the six electroweakinos (neutralinos and charginos) as the only other light new states. We combine 15 ATLAS and 12 CMS searches at 13\,TeV, along with a large collection of ATLAS and CMS measurements of Standard Model signatures. This model, which we refer to as the $\tilde G$-EWMSSM, exhibits quite varied collider phenomenology due to its many permitted electroweakino production processes and decay modes. Characteristic $\tilde G$-EWMSSM signal events have two or more Standard Model bosons and missing energy due to the escaping gravitinos. While much of the $\tilde G$-EWMSSM parameter space is excluded, we find several viable parameter regions that predict phenomenologically rich scenarios with multiple neutralinos and charginos within the kinematic reach of the LHC during Run 3, or the High Luminosity LHC. In particular, we identify scenarios with Higgsino-dominated electroweakinos as light as 140 GeV that are consistent with our combined set of collider searches and measurements. The full set of $\tilde G$-EWMSSM parameter samples and GAMBIT input files generated for this work is available via Zenodo. △ Less

Submitted 16 March, 2023; originally announced March 2023.

Comments: 38 pages, 12 figures, 5 tables

Report number: TTP23-009, KCL-PH-TH/2023-21, gambit-physics-23, MCnet-23-05, ADP-23-08/T1217, CERN-TH-2023-043

Global fits of simplified models for dark matter with GAMBIT II. Vector dark matter with an $s$-channel vector mediator

Authors: Christopher Chang, Pat Scott, Tomás E. Gonzalo, Felix Kahlhoefer, Martin White

Abstract: Global fits explore different parameter regions of a given model and apply constraints obtained at many energy scales. This makes it challenging to perform global fits of simplified models, which may not be valid at high energies. In this study, we derive a unitarity bound for a simplified vector dark matter model with an $s$-channel vector mediator, and apply it to global fits of this model with… ▽ More Global fits explore different parameter regions of a given model and apply constraints obtained at many energy scales. This makes it challenging to perform global fits of simplified models, which may not be valid at high energies. In this study, we derive a unitarity bound for a simplified vector dark matter model with an $s$-channel vector mediator, and apply it to global fits of this model with \GB in order to correctly interpret missing energy searches at the LHC. Two parameter space regions emerge as consistent with all experimental constraints, corresponding to different annihilation modes of the dark matter. We show that although these models are subject to strong validity constraints, they are currently most strongly constrained by measurements less sensitive to the high-energy behaviour of the theory. Understanding when these models cannot be consistently studied will become increasingly relevant as they are applied to LHC Run 3 data. △ Less

Submitted 7 August, 2023; v1 submitted 15 March, 2023; originally announced March 2023.

Comments: 15 pages, 7 figures, 3 tables, v2: matches EPJC version

Report number: gambit-physics-2023, TTP23-007, P3H-23-012, ADP-23-07/T1216

Journal ref: Eur. Phys. J. C 83, 692 (2023)

Global fits of simplified models for dark matter with GAMBIT I. Scalar and fermionic models with s-channel vector mediators

Authors: Christopher Chang, Pat Scott, Tomás E. Gonzalo, Felix Kahlhoefer, Anders Kvellestad, Martin White

Abstract: Simplified models provide a useful way to study the impacts of a small number of new particles on experimental observables and the interplay of those observables, without the need to construct an underlying theory. In this study, we perform global fits of simplified dark matter models with GAMBIT using an up-to-date set of likelihoods for indirect detection, direct detection and collider searches.… ▽ More Simplified models provide a useful way to study the impacts of a small number of new particles on experimental observables and the interplay of those observables, without the need to construct an underlying theory. In this study, we perform global fits of simplified dark matter models with GAMBIT using an up-to-date set of likelihoods for indirect detection, direct detection and collider searches. We investigate models in which a scalar or fermionic dark matter candidate couples to quarks via an s-channel vector mediator. Large parts of parameter space survive for each model. In the case of Dirac or Majorana fermion dark matter, excesses in LHC monojet searches and relic density limits tend to prefer the resonance region, where the dark matter has approximately half the mass of the mediator. A combination of vector and axial-vector couplings to the Dirac candidate also leads to competing constraints from direct detection and unitarity violation. △ Less

Submitted 7 August, 2023; v1 submitted 27 September, 2022; originally announced September 2022.

Comments: 21 pages, 11 figures, 4 tables, v2: matches EPJC version

Report number: gambit-physics-2022, TTP22-060, P3H-22-098, ADP-22-29/T1200

Journal ref: Eur. Phys. J. C 83, 249 (2023)

Report of the Topical Group on Physics Beyond the Standard Model at Energy Frontier for Snowmass 2021

Authors: Tulika Bose, Antonio Boveia, Caterina Doglioni, Simone Pagan Griso, James Hirschauer, Elliot Lipeles, Zhen Liu, Nausheen R. Shah, Lian-Tao Wang, Kaustubh Agashe, Juliette Alimena, Sebastian Baum, Mohamed Berkat, Kevin Black, Gwen Gardner, Tony Gherghetta, Josh Greaves, Maxx Haehn, Phil C. Harris, Robert Harris, Julie Hogan, Suneth Jayawardana, Abraham Kahn, Jan Kalinowski, Simon Knapen , et al. (297 additional authors not shown)

Abstract: This is the Snowmass2021 Energy Frontier (EF) Beyond the Standard Model (BSM) report. It combines the EF topical group reports of EF08 (Model-specific explorations), EF09 (More general explorations), and EF10 (Dark Matter at Colliders). The report includes a general introduction to BSM motivations and the comparative prospects for proposed future experiments for a broad range of potential BSM mode… ▽ More This is the Snowmass2021 Energy Frontier (EF) Beyond the Standard Model (BSM) report. It combines the EF topical group reports of EF08 (Model-specific explorations), EF09 (More general explorations), and EF10 (Dark Matter at Colliders). The report includes a general introduction to BSM motivations and the comparative prospects for proposed future experiments for a broad range of potential BSM models and signatures, including compositeness, SUSY, leptoquarks, more general new bosons and fermions, long-lived particles, dark matter, charged-lepton flavor violation, and anomaly detection. △ Less

Submitted 18 October, 2022; v1 submitted 26 September, 2022; originally announced September 2022.

Comments: 108 pages + 38 pages references and appendix, 37 figures, Report of the Topical Group on Beyond the Standard Model Physics at Energy Frontier for Snowmass 2021. The first nine authors are the Conveners, with Contributions from the other authors

Report of the Topical Group on Higgs Physics for Snowmass 2021: The Case for Precision Higgs Physics

Authors: Sally Dawson, Patrick Meade, Isobel Ojalvo, Caterina Vernieri, S. Adhikari, F. Abu-Ajamieh, A. Alberta, H. Bahl, R. Barman, M. Basso, A. Beniwal, I. Bozovi-Jelisav, S. Bright-Thonney, V. Cairo, F. Celiberto, S. Chang, M. Chen, C. Damerell, J. Davis, J. de Blas, W. Dekens, J. Duarte, D. Egana-Ugrinovic, U. Einhaus, Y. Gao , et al. (56 additional authors not shown)

Abstract: A future Higgs Factory will provide improved precision on measurements of Higgs couplings beyond those obtained by the LHC, and will enable a broad range of investigations across the fields of fundamental physics, including the mechanism of electroweak symmetry breaking, the origin of the masses and mixing of fundamental particles, the predominance of matter over antimatter, and the nature of dark… ▽ More A future Higgs Factory will provide improved precision on measurements of Higgs couplings beyond those obtained by the LHC, and will enable a broad range of investigations across the fields of fundamental physics, including the mechanism of electroweak symmetry breaking, the origin of the masses and mixing of fundamental particles, the predominance of matter over antimatter, and the nature of dark matter. Future colliders will measure Higgs couplings to a few per cent, giving a window to beyond the Standard Model (BSM) physics in the 1-10 TeV range. In addition, they will make precise measurements of the Higgs width, and characterize the Higgs self-coupling. This report details the work of the EF01 and EF02 working groups for the Snowmass 2021 study. △ Less

Submitted 20 December, 2022; v1 submitted 15 September, 2022; originally announced September 2022.

Comments: 44 pages, 40 figures, Report of the Topical Group on Higgs Physics for Snowmass 2021. The first four authors are the Conveners, with Contributions from the other authors

Cosmological constraints on decaying axion-like particles: a global analysis

Authors: Csaba Balázs, Sanjay Bloor, Tomás E. Gonzalo, Will Handley, Sebastian Hoof, Felix Kahlhoefer, Marie Lecroq, David J. E. Marsh, Janina J. Renk, Pat Scott, Patrick Stöcker

Abstract: Axion-like particles (ALPs) decaying into photons are known to affect a wide range of astrophysical and cosmological observables. In this study we focus on ALPs with masses in the keV-MeV range and lifetimes between $10^4$ and $10^{13}$ seconds, corresponding to decays between the end of Big Bang Nucleosynthesis and the formation of the Cosmic Microwave Background (CMB). Using the CosmoBit module… ▽ More Axion-like particles (ALPs) decaying into photons are known to affect a wide range of astrophysical and cosmological observables. In this study we focus on ALPs with masses in the keV-MeV range and lifetimes between $10^4$ and $10^{13}$ seconds, corresponding to decays between the end of Big Bang Nucleosynthesis and the formation of the Cosmic Microwave Background (CMB). Using the CosmoBit module of the global fitting framework GAMBIT, we combine state-of-the-art calculations of the irreducible ALP freeze-in abundance, primordial element abundances (including photodisintegration through ALP decays), CMB spectral distortions and anisotropies, and constraints from supernovae and stellar cooling. This approach makes it possible for the first time to perform a global analysis of the ALP parameter space while varying the parameters of $Λ$CDM as well as several nuisance parameters. We find a lower bound on the ALP mass of around $m_a > 300\,\text{keV}$, which can only be evaded if ALPs are stable on cosmological timescales. Future observations of CMB spectral distortions with a PIXIE-like mission are expected to improve this bound by two orders of magnitude. △ Less

Submitted 19 December, 2022; v1 submitted 26 May, 2022; originally announced May 2022.

Comments: 29+16 pages, 9 figures. V2 corresponds to the published version. Auxiliary material available on Zenodo at https://zenodo.org/record/6573347

Report number: gambit-physics-2022, KCL-PH-TH/2022-23, TTP22-034

Journal ref: JCAP 12 (2022) 027

Global fit of 2HDM with future collider results

Authors: Ankit Beniwal, Filip Rajec, Markus Tobias Prim, Pat Scott, Wei Su, Martin White, Anthony G. Williams, Alex Woodcock

Abstract: In this work, we summarize a global fit study of Type-II two Higgs doublet models (2HDM), and explore the impact of future SM-like Higgs and Z-pole precision measurements on the allowed parameter space. The work is based on the study results of a global fit of 2HDMs with the tool GAMBIT, utilising various current constraints including theoretical constraints (unitarity, perturbativity and vacuum s… ▽ More In this work, we summarize a global fit study of Type-II two Higgs doublet models (2HDM), and explore the impact of future SM-like Higgs and Z-pole precision measurements on the allowed parameter space. The work is based on the study results of a global fit of 2HDMs with the tool GAMBIT, utilising various current constraints including theoretical constraints (unitarity, perturbativity and vacuum stability), Higgs searches at colliders, electroweak physics and flavour constraints. We further investigate the ability of future facilities, such as the HL-LHC, CEPC, ILC and FCC-ee to explore the 2HDM parameter space. △ Less

Submitted 15 March, 2022; originally announced March 2022.

Comments: 9 pages, 3 plots, contribution to Snowmass 2021

Report number: KIAS--P22014, gambit-proceedings-2022

Simulation of energy transport by dark matter scattering in stars

Authors: Hannah Banks, Siyam Ansari, Aaron C. Vincent, Pat Scott

Abstract: Asymmetric dark matter (ADM) that is captured in stars can act as an efficient conductor of heat. Small ADM-induced changes in a star's temperature gradient are known to alter neutrino fluxes and asteroseismological signatures, erase convective cores and modify a star's main sequence lifetime. The Sun's proximity to us makes it an ideal laboratory for studying these effects. However, the two forma… ▽ More Asymmetric dark matter (ADM) that is captured in stars can act as an efficient conductor of heat. Small ADM-induced changes in a star's temperature gradient are known to alter neutrino fluxes and asteroseismological signatures, erase convective cores and modify a star's main sequence lifetime. The Sun's proximity to us makes it an ideal laboratory for studying these effects. However, the two formalisms commonly used to parametrize such heat transport were developed over 30 years ago, and calibrated with a single set of simulations. What's more, both are based on assumptions that break down at the Knudsen transition, where heat transport is maximized. We construct a Monte Carlo simulation to exactly solve the Boltzmann collision equation, determining the steady-state distribution and luminosity carried in stars by ADM with cross sections that depend on velocity and momentum. We find that, although the established (Gould and Raffelt) formalism based on local thermal equilibrium does well for constant cross sections, the isothermal (Spergel and Press) method actually performs better across all models with a simple, universal rescaling function. Based on simulation results, we provide recommendations on the parametrization of DM heat transport in stellar evolution models. △ Less

Submitted 2 June, 2022; v1 submitted 12 November, 2021; originally announced November 2021.

Comments: 38 pages, 14 figures. Updated to match published version

Journal ref: JCAP 04 (2022) 04, 002

The GAMBIT Universal Model Machine: from Lagrangians to Likelihoods

Authors: Sanjay Bloor, Tomás E. Gonzalo, Pat Scott, Christopher Chang, Are Raklev, José Eliel Camargo-Molina, Anders Kvellestad, Janina J. Renk, Peter Athron, Csaba Balázs

Abstract: We introduce the GAMBIT Universal Model Machine (GUM), a tool for automatically generating code for the global fitting software framework GAMBIT, based on Lagrangian-level inputs. GUM accepts models written symbolically in FeynRules and SARAH formats, and can use either tool along with MadGraph and CalcHEP to generate GAMBIT model, collider, dark matter, decay and spectrum code, as well as GAMBIT… ▽ More We introduce the GAMBIT Universal Model Machine (GUM), a tool for automatically generating code for the global fitting software framework GAMBIT, based on Lagrangian-level inputs. GUM accepts models written symbolically in FeynRules and SARAH formats, and can use either tool along with MadGraph and CalcHEP to generate GAMBIT model, collider, dark matter, decay and spectrum code, as well as GAMBIT interfaces to corresponding versions of SPheno, micrOMEGAs, Pythia and Vevacious (C++). In this paper we describe the features, methods, usage, pathways, assumptions and current limitations of GUM. We also give a fully worked example, consisting of the addition of a Majorana fermion simplified dark matter model with a scalar mediator to GAMBIT via GUM, and carry out a corresponding fit. △ Less

Submitted 15 December, 2021; v1 submitted 30 June, 2021; originally announced July 2021.

Comments: 32 pages, 6 figures, 3 tables

Report number: TTK-21-24, gambit-code-2021

Journal ref: Eur. Phys. J. C 81, 1103 (2021)

Thermal WIMPs and the Scale of New Physics: Global Fits of Dirac Dark Matter Effective Field Theories

Authors: The GAMBIT Collaboration, Peter Athron, Neal Avis Kozar, Csaba Balázs, Ankit Beniwal, Sanjay Bloor, Torsten Bringmann, Joachim Brod, Christopher Chang, Jonathan M. Cornell, Ben Farmer, Andrew Fowlie, Tomás E. Gonzalo, Will Handley, Felix Kahlhoefer, Anders Kvellestad, Farvah Mahmoudi, Markus T. Prim, Are Raklev, Janina J. Renk, Andre Scaffidi, Pat Scott, Patrick Stöcker, Aaron C. Vincent, Martin White , et al. (2 additional authors not shown)

Abstract: We assess the status of a wide class of WIMP dark matter (DM) models in light of the latest experimental results using the global fitting framework $\textsf{GAMBIT}$. We perform a global analysis of effective field theory (EFT) operators describing the interactions between a gauge-singlet Dirac fermion and the Standard Model quarks, the gluons and the photon. In this bottom-up approach, we simulta… ▽ More We assess the status of a wide class of WIMP dark matter (DM) models in light of the latest experimental results using the global fitting framework $\textsf{GAMBIT}$. We perform a global analysis of effective field theory (EFT) operators describing the interactions between a gauge-singlet Dirac fermion and the Standard Model quarks, the gluons and the photon. In this bottom-up approach, we simultaneously vary the coefficients of 14 such operators up to dimension 7, along with the DM mass, the scale of new physics and several nuisance parameters. Our likelihood functions include the latest data from $\mathit{Planck}$, direct and indirect detection experiments, and the LHC. For DM masses below 100 GeV, we find that it is impossible to satisfy all constraints simultaneously while maintaining EFT validity at LHC energies. For new physics scales around 1 TeV, our results are influenced by several small excesses in the LHC data and depend on the prescription that we adopt to ensure EFT validity. Furthermore, we find large regions of viable parameter space where the EFT is valid and the relic density can be reproduced, implying that WIMPs can still account for the DM of the universe while being consistent with the latest data. △ Less

Submitted 13 November, 2021; v1 submitted 3 June, 2021; originally announced June 2021.

Comments: 37 pages, 11 figures, 5 tables; v2: matches EPJC version

Report number: ADP-21-9/T1156, CERN-TH-2021-084, CP3-21-15, P3H-21-038, TTK-21-19, gambit-physics-2021

Journal ref: Eur. Phys. J. C 81, 992 (2021)

Capt'n General: A generalized stellar dark matter capture and heat transport code

Authors: Neal Avis Kozar, Ashlee Caddell, Luke Fraser-Leach, Pat Scott, Aaron C. Vincent

Abstract: Capt'n General is a FORTRAN90 standalone package that can be used to compute the capture and heat transport of dark matter in stars. It can compute capture rates for constant, velocity and momentum-dependent DM-nucleon elastic scattering cross sections, as well as non-relativistic effective operator interactions. Capt'n General can be interfaced with the GAMBIT global fitting codebase as well as s… ▽ More Capt'n General is a FORTRAN90 standalone package that can be used to compute the capture and heat transport of dark matter in stars. It can compute capture rates for constant, velocity and momentum-dependent DM-nucleon elastic scattering cross sections, as well as non-relativistic effective operator interactions. Capt'n General can be interfaced with the GAMBIT global fitting codebase as well as stellar evolution simulation codes such as MESA. △ Less

Submitted 14 May, 2021; originally announced May 2021.

Comments: 9 pages, 2 figures. Loosely based on a talk presented at TOOLS2020. Code available at: https://github.com/aaronvincent/captngen

A comparison of optimisation algorithms for high-dimensional particle and astrophysics applications

Authors: The DarkMachines High Dimensional Sampling Group, Csaba Balázs, Melissa van Beekveld, Sascha Caron, Barry M. Dillon, Ben Farmer, Andrew Fowlie, Eduardo C. Garrido-Merchán, Will Handley, Luc Hendriks, Guðlaugur Jóhannesson, Adam Leinweber, Judita Mamužić, Gregory D. Martinez, Sydney Otten, Pat Scott, Roberto Ruiz de Austri, Zachary Searle, Bob Stienen, Joaquin Vanschoren, Martin White

Abstract: Optimisation problems are ubiquitous in particle and astrophysics, and involve locating the optimum of a complicated function of many parameters that may be computationally expensive to evaluate. We describe a number of global optimisation algorithms that are not yet widely used in particle astrophysics, benchmark them against random sampling and existing techniques, and perform a detailed compari… ▽ More Optimisation problems are ubiquitous in particle and astrophysics, and involve locating the optimum of a complicated function of many parameters that may be computationally expensive to evaluate. We describe a number of global optimisation algorithms that are not yet widely used in particle astrophysics, benchmark them against random sampling and existing techniques, and perform a detailed comparison of their performance on a range of test functions. These include four analytic test functions of varying dimensionality, and a realistic example derived from a recent global fit of weak-scale supersymmetry. Although the best algorithm to use depends on the function being investigated, we are able to present general conclusions about the relative merits of random sampling, Differential Evolution, Particle Swarm Optimisation, the Covariance Matrix Adaptation Evolution Strategy, Bayesian Optimisation, Grey Wolf Optimisation, and the PyGMO Artificial Bee Colony, Gaussian Particle Filter and Adaptive Memory Programming for Global Optimisation algorithms. △ Less

Submitted 1 April, 2021; v1 submitted 12 January, 2021; originally announced January 2021.

Comments: Experimental framework publicly available at http://www.github.com/darkmachines/high-dimensional-sampling

Simple and statistically sound recommendations for analysing physical theories

Authors: Shehu S. AbdusSalam, Fruzsina J. Agocs, Benjamin C. Allanach, Peter Athron, Csaba Balázs, Emanuele Bagnaschi, Philip Bechtle, Oliver Buchmueller, Ankit Beniwal, Jihyun Bhom, Sanjay Bloor, Torsten Bringmann, Andy Buckley, Anja Butter, José Eliel Camargo-Molina, Marcin Chrzaszcz, Jan Conrad, Jonathan M. Cornell, Matthias Danninger, Jorge de Blas, Albert De Roeck, Klaus Desch, Matthew Dolan, Herbert Dreiner, Otto Eberhardt , et al. (50 additional authors not shown)

Abstract: Physical theories that depend on many parameters or are tested against data from many different experiments pose unique challenges to statistical inference. Many models in particle physics, astrophysics and cosmology fall into one or both of these categories. These issues are often sidestepped with statistically unsound ad hoc methods, involving intersection of parameter intervals estimated by mul… ▽ More Physical theories that depend on many parameters or are tested against data from many different experiments pose unique challenges to statistical inference. Many models in particle physics, astrophysics and cosmology fall into one or both of these categories. These issues are often sidestepped with statistically unsound ad hoc methods, involving intersection of parameter intervals estimated by multiple experiments, and random or grid sampling of model parameters. Whilst these methods are easy to apply, they exhibit pathologies even in low-dimensional parameter spaces, and quickly become problematic to use and interpret in higher dimensions. In this article we give clear guidance for going beyond these procedures, suggesting where possible simple methods for performing statistically sound inference, and recommendations of readily-available software tools and standards that can assist in doing so. Our aim is to provide any physicists lacking comprehensive statistical training with recommendations for reaching correct scientific conclusions, with only a modest increase in analysis burden. Our examples can be reproduced with the code publicly available at https://doi.org/10.5281/zenodo.4322283. △ Less

Submitted 11 April, 2022; v1 submitted 17 December, 2020; originally announced December 2020.

Comments: 15 pages, 4 figures. extended discussions. closely matches version accepted for publication

Report number: PSI-PR-20-23, BONN-TH-2020-11, CP3-20-59, KCL-PH-TH/2020-75, P3H-20-080, TTP20-044, TUM-HEP-1310/20, IFT-UAM/CSIC-20-180, TTK-20-47, CERN-TH-2020-215, FTPI-MINN-20-36, UMN-TH-4005/20, HU-EP-20/37, DESY 20-222, ADP-20-33/T1143, Imperial/TP/2020/RT/04, UCI-TR-2020-19, gambit-review-2020

Journal ref: Rep. Prog. Phys. 85 052201 (2022)

Strengthening the bound on the mass of the lightest neutrino with terrestrial and cosmological experiments

Authors: The GAMBIT Cosmology Workgroup, :, Patrick Stöcker, Csaba Balázs, Sanjay Bloor, Torsten Bringmann, Tomás E. Gonzalo, Will Handley, Selim Hotinli, Cullan Howlett, Felix Kahlhoefer, Janina J. Renk, Pat Scott, Aaron C. Vincent, Martin White

Abstract: We determine the upper limit on the mass of the lightest neutrino from the most robust recent cosmological and terrestrial data. Marginalizing over possible effective relativistic degrees of freedom at early times ($N_\mathrm{eff}$) and assuming normal mass ordering, the mass of the lightest neutrino is less than 0.037 eV at 95% confidence; with inverted ordering, the bound is 0.042 eV. These resu… ▽ More We determine the upper limit on the mass of the lightest neutrino from the most robust recent cosmological and terrestrial data. Marginalizing over possible effective relativistic degrees of freedom at early times ($N_\mathrm{eff}$) and assuming normal mass ordering, the mass of the lightest neutrino is less than 0.037 eV at 95% confidence; with inverted ordering, the bound is 0.042 eV. These results improve upon the strength and robustness of other recent limits and constrain the mass of the lightest neutrino to be barely larger than the largest mass splitting. We show the impacts of realistic mass models, and different sources of $N_\mathrm{eff}$. △ Less

Submitted 6 June, 2021; v1 submitted 7 September, 2020; originally announced September 2020.

Comments: 5 pages, 2 figures + Appendix. Full dataset available at https://doi.org/10.5281/zenodo.4005381 (v3: Matches version published in PRD)

Report number: TTK-20-28, gambit-physics-2020

Journal ref: Phys. Rev. D 103, 123508 (2021)

CosmoBit: A GAMBIT module for computing cosmological observables and likelihoods

Authors: The GAMBIT Cosmology Workgroup, :, Janina J. Renk, Patrick Stöcker, Sanjay Bloor, Selim Hotinli, Csaba Balázs, Torsten Bringmann, Tomás E. Gonzalo, Will Handley, Sebastian Hoof, Cullan Howlett, Felix Kahlhoefer, Pat Scott, Aaron C. Vincent, Martin White

Abstract: We introduce $\sf{CosmoBit}$, a module within the open-source $\sf{GAMBIT}$ software framework for exploring connections between cosmology and particle physics with joint global fits. $\sf{CosmoBit}$ provides a flexible framework for studying various scenarios beyond $Λ$CDM, such as models of inflation, modifications of the effective number of relativistic degrees of freedom, exotic energy injecti… ▽ More We introduce $\sf{CosmoBit}$, a module within the open-source $\sf{GAMBIT}$ software framework for exploring connections between cosmology and particle physics with joint global fits. $\sf{CosmoBit}$ provides a flexible framework for studying various scenarios beyond $Λ$CDM, such as models of inflation, modifications of the effective number of relativistic degrees of freedom, exotic energy injection from annihilating or decaying dark matter, and variations of the properties of elementary particles such as neutrino masses and the lifetime of the neutron. Many observables and likelihoods in $\sf{CosmoBit}$ are computed via interfaces to $\sf{AlterBBN}$, $\sf{CLASS}$, $\sf{DarkAges}$, $\sf{MontePython}$, $\sf{MultiModeCode}$, and $\sf{plc}$. This makes it possible to apply a wide range of constraints from large-scale structure, Type Ia supernovae, Big Bang Nucleosynthesis and the cosmic microwave background. Parameter scans can be performed using the many different statistical sampling algorithms available within the $\sf{GAMBIT}$ framework, and results can be combined with calculations from other $\sf{GAMBIT}$ modules focused on particle physics and dark matter. We include extensive validation plots and a first application to scenarios with non-standard relativistic degrees of freedom and neutrino temperature, showing that the corresponding constraint on the sum of neutrino masses is much weaker than in the standard scenario. △ Less

Submitted 10 February, 2021; v1 submitted 7 September, 2020; originally announced September 2020.

Comments: 44 pages (including executive summary), 11 figures + appendices. Code available at https://github.com/GambitBSM/gambit_1.5 and all datasets available at https://doi.org/10.5281/zenodo.3975642 . V3: minor revisions, matches published version

Report number: gambit-code-2020, TTK-20-27

Journal ref: JCAP 02 (2021) 022

Self-consistent approach for measuring the energy spectra and composition of cosmic rays and determining the properties of hadronic interactions at high energy

Authors: Andrea Addazi, Andy Buckley, Jose Bellido, Zhen Cao, Ruben Conceição, Lorenzo Cazon, Armando di Matteo, Bruce Dawson, Kasumasa Kawata, Paolo Lipari, Analiza Mariazzi, Marco Muzio, Shoichi Ogio, Sergey Ostapchenko, Mário Pimenta, Tanguy Pierog, Andres Romero-Wolf, Felix Riehn, David Schmidt, Eva Santos, Frank Schroeder, Karen Caballero-Mora, Pat Scott, Takashi Sako, Carlos Todero Peixoto , et al. (3 additional authors not shown)

Abstract: Air showers, produced by the interaction of energetic cosmic rays with the atmosphere, are an excellent alternative to study particle physics at energies beyond any human-made particle accelerator. For that, it is necessary to identify first the mass composition of the primary cosmic ray (and its energy). None of the existing high energy interaction models have been able to reproduce coherently al… ▽ More Air showers, produced by the interaction of energetic cosmic rays with the atmosphere, are an excellent alternative to study particle physics at energies beyond any human-made particle accelerator. For that, it is necessary to identify first the mass composition of the primary cosmic ray (and its energy). None of the existing high energy interaction models have been able to reproduce coherently all air shower observables over the entire energy and zenith angle phase space. This is despite having tried all possible combinations for the cosmic ray mass composition. This proposal outlines a self-consistent strategy to study high energy particle interactions and identify the energy spectra and mass composition of cosmic rays. This strategy involves the participation of different particle accelerators and astrophysics experiments. This is important to cover the entire cosmic ray energy range and a larger phase-space of shower observables to probe the high energy interaction models. △ Less

Submitted 2 September, 2020; originally announced September 2020.

Comments: Snowmass2021 - Letter of Interest

Global fits of axion-like particles to XENON1T and astrophysical data

Authors: Peter Athron, Csaba Balázs, Ankit Beniwal, J. Eliel Camargo-Molina, Andrew Fowlie, Tomás E. Gonzalo, Sebastian Hoof, Felix Kahlhoefer, David J. E. Marsh, Markus Tobias Prim, Andre Scaffidi, Pat Scott, Wei Su, Martin White, Lei Wu, Yang Zhang

Abstract: The excess of electron recoil events seen by the XENON1T experiment has been interpreted as a potential signal of axion-like particles (ALPs), either produced in the Sun, or constituting part of the dark matter halo of the Milky Way. It has also been explained as a consequence of trace amounts of tritium in the experiment. We consider the evidence for the solar and dark-matter ALP hypotheses from… ▽ More The excess of electron recoil events seen by the XENON1T experiment has been interpreted as a potential signal of axion-like particles (ALPs), either produced in the Sun, or constituting part of the dark matter halo of the Milky Way. It has also been explained as a consequence of trace amounts of tritium in the experiment. We consider the evidence for the solar and dark-matter ALP hypotheses from the combination of XENON1T data and multiple astrophysical probes, including horizontal branch stars, red giants, and white dwarfs. We briefly address the influence of ALP decays and supernova cooling. While the different datasets are in clear tension for the case of solar ALPs, all measurements can be simultaneously accommodated for the case of a sub-dominant fraction of dark-matter ALPs. Nevertheless, this solution requires the tuning of several a priori unknown parameters, such that for our choices of priors a Bayesian analysis shows no strong preference for the ALP interpretation of the XENON1T excess over the background hypothesis. △ Less

Submitted 19 April, 2021; v1 submitted 10 July, 2020; originally announced July 2020.

Comments: 40 pages, 9 figures. V3 corresponds to the accepted manuscript; added appendices on the DIC and MC simulations; supplementary material now available on Zenodo at https://doi.org/10.5281/zenodo.4384061

Report number: CP3-20-36, TTK-20-21, CoEPP-MN-20-5, ADP-20-22/T1132, gambit-physics-2020

Journal ref: J. High Energ. Phys. 2021, 159 (2021)

$\textsf{Xsec}$: the cross-section evaluation code

Authors: Andy Buckley, Anders Kvellestad, Are Raklev, Pat Scott, Jon Vegard Sparre, Jeriek Van den Abeele, Ingrid A. Vazquez-Holm

Abstract: The evaluation of higher-order cross-sections is an important component in the search for new physics, both at hadron colliders and elsewhere. For most new physics processes of interest, total cross-sections are known at next-to-leading order (NLO) in the strong coupling $α_s$, and often beyond, via either higher-order terms at fixed powers of $α_s$, or multi-emission resummation. However, the com… ▽ More The evaluation of higher-order cross-sections is an important component in the search for new physics, both at hadron colliders and elsewhere. For most new physics processes of interest, total cross-sections are known at next-to-leading order (NLO) in the strong coupling $α_s$, and often beyond, via either higher-order terms at fixed powers of $α_s$, or multi-emission resummation. However, the computation time for such higher-order cross-sections is prohibitively expensive, and precludes efficient evaluation in parameter-space scans beyond two dimensions. Here we describe the software tool $\textsf{xsec}$, which allows for fast evaluation of cross-sections based on the use of machine-learning regression, using distributed Gaussian processes trained on a pre-generated sample of parameter points. This first version of the code provides all NLO Minimal Supersymmetric Standard Model strong-production cross-sections at the LHC, for individual flavour final states, evaluated in a fraction of a second. Moreover, it calculates regression errors, as well as estimates of errors from higher-order contributions, from uncertainties in the parton distribution functions, and from the value of $α_s$. While we focus on a specific phenomenological model of supersymmetry, the method readily generalises to any process where it is possible to generate a sufficient training sample. △ Less

Submitted 18 December, 2020; v1 submitted 29 June, 2020; originally announced June 2020.

Comments: Accepted version

Report number: SAGEX-20-17-E

Journal ref: Eur. Phys. J. C 80, 1106 (2020)

A model-independent analysis of $b \to s μ^+ μ^-$ transitions with GAMBIT's FlavBit

Authors: J. Bhom, M. Chrzaszcz, F. Mahmoudi, M. T. Prim, P. Scott, M. White

Abstract: The search for flavour-changing neutral current effects in $B$-meson decays is a powerful probe of physics beyond the Standard Model. Deviations from SM behaviour are often quantified by extracting the preferred values of the Wilson coefficients of an operator product expansion. We use the FlavBit module of the GAMBIT package to perform a simultaneous global fit of the Wilson coefficients $C_7$,… ▽ More The search for flavour-changing neutral current effects in $B$-meson decays is a powerful probe of physics beyond the Standard Model. Deviations from SM behaviour are often quantified by extracting the preferred values of the Wilson coefficients of an operator product expansion. We use the FlavBit module of the GAMBIT package to perform a simultaneous global fit of the Wilson coefficients $C_7$, $C_9$, and $C_{10}$ using a combination of all current data on $b \to s μ^+ μ^-$ transitions. We further extend previous analyses by accounting for the correlated theoretical uncertainties at each point in the Wilson coefficient parameter space, rather than deriving the uncertainties from a Standard Model calculation. We find that the best fit deviates from the SM value with a significance of 6.6$σ$. The largest deviation is associated with a vector coupling of muons to $b$ and $s$ quarks. △ Less

Submitted 14 December, 2021; v1 submitted 5 June, 2020; originally announced June 2020.

Comments: 28 pages, 6 figures. v2: updated including recent experimental measurements (e.g. LHCb angular analysis of $B^+ \to K^{*+} μ^+ μ^-$ and LHCb and Belle angular analysis of $B \to K^* e^+ e^-$) in the fit

Report number: CERN-TH-2020-089, gambit-physics-2020

Journal ref: Eur. Phys. J. C 81 (2021) 12, 1076

Reinterpretation of LHC Results for New Physics: Status and Recommendations after Run 2

Authors: Waleed Abdallah, Shehu AbdusSalam, Azar Ahmadov, Amine Ahriche, Gaël Alguero, Benjamin C. Allanach, Jack Y. Araz, Alexandre Arbey, Chiara Arina, Peter Athron, Emanuele Bagnaschi, Yang Bai, Michael J. Baker, Csaba Balazs, Daniele Barducci, Philip Bechtle, Aoife Bharucha, Andy Buckley, Jonathan Butterworth, Haiying Cai, Claudio Campagnari, Cari Cesarotti, Marcin Chrzaszcz, Andrea Coccaro, Eric Conte , et al. (117 additional authors not shown)

Abstract: We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentati… ▽ More We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentation of LHC results in order to better enable reinterpretation in the future. We also provide a brief description of existing software reinterpretation frameworks and recent global analyses of new physics that make use of the current data. △ Less

Submitted 21 July, 2020; v1 submitted 17 March, 2020; originally announced March 2020.

Comments: 58 pages, minor revision following comments from SciPost referees

Report number: CERN-LPCC-2020-001, FERMILAB-FN-1098-CMS-T, Imperial/HEP/2020/RIF/01

Journal ref: SciPost Phys. 9, 022 (2020)

GAMBIT and its Application in the Search for Physics Beyond the Standard Model

Authors: Anders Kvellestad, Pat Scott, Martin White

Abstract: The Global and Modular Beyond-Standard Model Inference Tool (GAMBIT) is an open source software framework for performing global statistical fits of particle physics models, using a wide range of particle and astroparticle data. In this review, we describe the design principles of the package, the statistical and sampling frameworks, the experimental data included, and the first two years of physic… ▽ More The Global and Modular Beyond-Standard Model Inference Tool (GAMBIT) is an open source software framework for performing global statistical fits of particle physics models, using a wide range of particle and astroparticle data. In this review, we describe the design principles of the package, the statistical and sampling frameworks, the experimental data included, and the first two years of physics results generated with it. This includes supersymmetric models, axion theories, Higgs portal dark matter scenarios and an extension of the Standard Model to include right-handed neutrinos. Owing to the broad spectrum of physics scenarios tackled by the GAMBIT community, this also serves as a convenient, self-contained review of the current experimental and theoretical status of the most popular models of dark matter. △ Less

Submitted 19 March, 2020; v1 submitted 6 December, 2019; originally announced December 2019.

Comments: 108 pages, 28 figures, 3 tables; matches version accepted by Progress in Particle and Nuclear Physics; v3 includes a small correction to the acknowledgements

Report number: gambit-physics-2019, gambit-code-2019

Dark energy without fine tuning

Authors: José Eliel Camargo-Molina, Tommi Markkanen, Pat Scott

Abstract: We present a two-field model that realises inflation and the observed density of dark energy today, whilst solving the fine-tuning problems inherent in quintessence models. One field acts as the inflaton, generically driving the other to a saddle-point of the potential, from which it acts as a quintessence field following electroweak symmetry breaking. The model exhibits essentially no sensitivity… ▽ More We present a two-field model that realises inflation and the observed density of dark energy today, whilst solving the fine-tuning problems inherent in quintessence models. One field acts as the inflaton, generically driving the other to a saddle-point of the potential, from which it acts as a quintessence field following electroweak symmetry breaking. The model exhibits essentially no sensitivity to the initial value of the quintessence field, naturally suppresses its interactions with other fields, and automatically endows it with a small effective mass in the late Universe. The magnitude of dark energy today is fixed by the height of the saddle point in the potential, which is dictated entirely by the scale of electroweak symmetry breaking. △ Less

Submitted 16 September, 2019; v1 submitted 30 April, 2019; originally announced May 2019.

Comments: v2: 13 pages, minor improvements, version accepted in JHEP

Report number: IMPERIAL/TP/2019/TM/04

Journal ref: JHEP 1901 (2019) 044

Axion global fits with Peccei-Quinn symmetry breaking before inflation using GAMBIT

Authors: Sebastian Hoof, Felix Kahlhoefer, Pat Scott, Christoph Weniger, Martin White

Abstract: We present global fits of cosmologically stable axion-like particle and QCD axion models in the mass range 0.1 neV to 10 eV. We focus on the case where the Peccei-Quinn symmetry is broken before the end of inflation, such that the initial value of the axion field can be considered to be homogeneous throughout the visible Universe. We include detailed likelihood functions from light-shining-through… ▽ More We present global fits of cosmologically stable axion-like particle and QCD axion models in the mass range 0.1 neV to 10 eV. We focus on the case where the Peccei-Quinn symmetry is broken before the end of inflation, such that the initial value of the axion field can be considered to be homogeneous throughout the visible Universe. We include detailed likelihood functions from light-shining-through-wall experiments, haloscopes, helioscopes, the axion relic density, horizontal branch stars, supernova 1987A, white dwarf cooling, and gamma-ray observations. We carry out both frequentist and Bayesian analyses, with and without the inclusion of white dwarf cooling. We explore the degree of fine-tuning present in different models and identify parameter regions where it is possible for QCD axion models to account for both the dark matter in the Universe and the cooling hints, comparing them to specific DFSZ- and KSVZ-type models. We find the most credible parameter regions, allowing us to set (prior-dependent) upper and lower bounds on the axion mass. Our analysis also suggests that QCD axions in this scenario most probably make up a non-negligible but sub-dominant component of the dark matter in the Universe. △ Less

Submitted 17 October, 2019; v1 submitted 16 October, 2018; originally announced October 2018.

Comments: 77 pages, 29 figures. Version v3: revised version of the paper due to a bug in the code (see Footnote 2); please use GAMBIT 1.3.1 or newer. Updated supplementary material available on Zenodo (version v3) at http://dx.doi.org/10.5281/zenodo.2615235

Report number: gambit-physics-2018

Journal ref: J. High Energ. Phys. 03 (2019) 191

Combined collider constraints on neutralinos and charginos

Authors: The GAMBIT Collaboration, Peter Athron, Csaba Balázs, Andy Buckley, Jonathan M. Cornell, Matthias Danninger, Ben Farmer, Andrew Fowlie, Tomás E. Gonzalo, Julia Harz, Paul Jackson, Rose Kudzman-Blais, Anders Kvellestad, Gregory D. Martinez, Andreas Petridis, Are Raklev, Christopher Rogan, Pat Scott, Abhishek Sharma, Martin White, Yang Zhang

Abstract: Searches for supersymmetric electroweakinos have entered a crucial phase, as the integrated luminosity of the Large Hadron Collider is now high enough to compensate for their weak production cross-sections. Working in a framework where the neutralinos and charginos are the only light sparticles in the Minimal Supersymmetric Standard Model, we use gambit to perform a detailed likelihood analysis of… ▽ More Searches for supersymmetric electroweakinos have entered a crucial phase, as the integrated luminosity of the Large Hadron Collider is now high enough to compensate for their weak production cross-sections. Working in a framework where the neutralinos and charginos are the only light sparticles in the Minimal Supersymmetric Standard Model, we use gambit to perform a detailed likelihood analysis of the electroweakino sector. We focus on the impacts of recent ATLAS and CMS searches with 36 fb$^{-1}$ of 13 TeV proton-proton collision data. We also include constraints from LEP and invisible decays of the $Z$ and Higgs bosons. Under the background-only hypothesis, we show that current LHC searches do not robustly exclude any range of neutralino or chargino masses. However, a pattern of excesses in several LHC analyses points towards a possible signal, with neutralino masses of $(m_{\tildeχ_1^0}, m_{\tildeχ_2^0}, m_{\tildeχ_3^0}, m_{\tildeχ_4^0})$ = (8-155, 103-260, 130-473, 219-502) GeV and chargino masses of $(m_{\tildeχ_1^{\pm}}, m_{\tildeχ_2^{\pm}})$ = (104-259, 224-507) GeV at the 95% confidence level. The lightest neutralino is mostly bino, with a possible modest Higgsino or wino component. We find that this excess has a combined local significance of $3.3σ$, subject to a number of cautions. If one includes LHC searches for charginos and neutralinos conducted with 8 TeV proton-proton collision data, the local significance is lowered to 2.9$σ$. We briefly consider the implications for dark matter, finding that the correct relic density can be obtained through the Higgs-funnel and $Z$-funnel mechanisms, even assuming that all other sparticles are decoupled. All samples, gambit input files and best-fit models from this study are available on Zenodo. △ Less

Submitted 20 June, 2019; v1 submitted 6 September, 2018; originally announced September 2018.

Comments: 38 pages, 16 figures, v3 is the version accepted by EPJC

Report number: CoEPP-MN-18-7, gambit-physics-2018

Journal ref: Eur.Phys.J. C79 (2019) no.5, 395

Global analyses of Higgs portal singlet dark matter models using GAMBIT

Authors: The GAMBIT Collaboration, Peter Athron, Csaba Balázs, Ankit Beniwal, Sanjay Bloor, José Eliel Camargo-Molina, Jonathan M. Cornell, Ben Farmer, Andrew Fowlie, Tomás E. Gonzalo, Felix Kahlhoefer, Anders Kvellestad, Gregory D. Martinez, Pat Scott, Aaron C. Vincent, Sebastian Wild, Martin White, Anthony G. Williams

Abstract: We present global analyses of effective Higgs portal dark matter models in the frequentist and Bayesian statistical frameworks. Complementing earlier studies of the scalar Higgs portal, we use GAMBIT to determine the preferred mass and coupling ranges for models with vector, Majorana and Dirac fermion dark matter. We also assess the relative plausibility of all four models using Bayesian model com… ▽ More We present global analyses of effective Higgs portal dark matter models in the frequentist and Bayesian statistical frameworks. Complementing earlier studies of the scalar Higgs portal, we use GAMBIT to determine the preferred mass and coupling ranges for models with vector, Majorana and Dirac fermion dark matter. We also assess the relative plausibility of all four models using Bayesian model comparison. Our analysis includes up-to-date likelihood functions for the dark matter relic density, invisible Higgs decays, and direct and indirect searches for weakly-interacting dark matter including the latest XENON1T data. We also account for important uncertainties arising from the local density and velocity distribution of dark matter, nuclear matrix elements relevant to direct detection, and Standard Model masses and couplings. In all Higgs portal models, we find parameter regions that can explain all of dark matter and give a good fit to all data. The case of vector dark matter requires the most tuning and is therefore slightly disfavoured from a Bayesian point of view. In the case of fermionic dark matter, we find a strong preference for including a CP-violating phase that allows suppression of constraints from direct detection experiments, with odds in favour of CP violation of the order of 100:1. Finally, we present DDCalc 2.0.0, a tool for calculating direct detection observables and likelihoods for arbitrary non-relativistic effective operators. △ Less

Submitted 31 July, 2020; v1 submitted 30 August, 2018; originally announced August 2018.

Comments: 30 pages, 12 figures. v2 matches the published version

Report number: ADP-18-22/T1070, COEPP-MN-18-6, DESY-18-141, TTK-18-34, gambit-physics-2018

Journal ref: Eur.Phys.J. C79 (2019) no.1, 38

Statistical challenges in the search for dark matter

Authors: Sara Algeri, Melissa van Beekveld, Nassim Bozorgnia, Alyson Brooks, J. Alberto Casas, Jessi Cisewski-Kehe, Francis-Yan Cyr-Racine, Thomas D. P. Edwards, Fabio Iocco, Bradley J. Kavanagh, Judita Mamužić, Siddharth Mishra-Sharma, Wolfgang Rau, Roberto Ruiz de Austri, Benjamin R. Safdi, Pat Scott, Tracy R. Slatyer, Yue-Lin Sming Tsai, Aaron C. Vincent, Christoph Weniger, Jennifer Rittenhouse West, Robert L. Wolpert

Abstract: The search for the particle nature of dark matter has given rise to a number of experimental, theoretical and statistical challenges. Here, we report on a number of these statistical challenges and new techniques to address them, as discussed in the DMStat workshop held Feb 26 - Mar 3 2018 at the Banff International Research Station for Mathematical Innovation and Discovery (BIRS) in Banff, Albert… ▽ More The search for the particle nature of dark matter has given rise to a number of experimental, theoretical and statistical challenges. Here, we report on a number of these statistical challenges and new techniques to address them, as discussed in the DMStat workshop held Feb 26 - Mar 3 2018 at the Banff International Research Station for Mathematical Innovation and Discovery (BIRS) in Banff, Alberta. △ Less

Submitted 24 July, 2018; originally announced July 2018.

Comments: 32 pages, 8 figures, 331 references

Report number: IPPP/18/60

Impact of vacuum stability, perturbativity and XENON1T on global fits of $\mathbb{Z}_2$ and $\mathbb{Z}_3$ scalar singlet dark matter

Authors: Peter Athron, Jonathan M. Cornell, Felix Kahlhoefer, James McKay, Pat Scott, Sebastian Wild

Abstract: Scalar singlet dark matter is one of the simplest and most predictive realisations of the WIMP (weakly-interacting massive particle) idea. Although the model is constrained from all directions by the latest experimental data, it still has viable regions of parameter space. Another compelling aspect of scalar singlets is their ability to stabilise the electroweak vacuum. Indeed, models of scalar da… ▽ More Scalar singlet dark matter is one of the simplest and most predictive realisations of the WIMP (weakly-interacting massive particle) idea. Although the model is constrained from all directions by the latest experimental data, it still has viable regions of parameter space. Another compelling aspect of scalar singlets is their ability to stabilise the electroweak vacuum. Indeed, models of scalar dark matter are not low-energy effective theories, but can be valid all the way to the Planck scale. Using the GAMBIT framework, we present the first global fit to include both the low-energy experimental constraints and the theoretical constraints from UV physics, considering models with a scalar singlet charged under either a $\mathbb{Z}_2$ or a $\mathbb{Z}_3$ symmetry. We show that if the model is to satisfy all experimental constraints, completely stabilise the electroweak vacuum up to high scales, and also remain perturbative to those scales, one is driven to a relatively small region of parameter space. This region has a Higgs-portal coupling slightly less than 1, a dark matter mass of 1 to 2 TeV and a spin-independent nuclear scattering cross-section around 10$^{-45}$ cm$^2$. △ Less

Submitted 19 October, 2018; v1 submitted 29 June, 2018; originally announced June 2018.

Comments: 25 pages, 13 figures. v2 matches the published version. Supplementary data available at https://doi.org/10.5281/zenodo.1298565

Report number: TTK-18-21, DESY 18-102, CoEPP-MN-18-3, gambit-physics-2018

Journal ref: Eur. Phys. J. C 78, 830 (2018)

Global analyses of supersymmetry with GAMBIT

Authors: Pat Scott

Abstract: I provide a brief summary of the status of supersymmetric models with parameters defined at either the unification or weak scale, based on global fits using the GAMBIT framework. I provide a brief summary of the status of supersymmetric models with parameters defined at either the unification or weak scale, based on global fits using the GAMBIT framework. △ Less

Submitted 15 May, 2018; originally announced May 2018.

Comments: 4 pages, 3 figures, proceedings of invited contribution to Rencontres de Moriond QCD 2018

Report number: gambit-proceedings-2018

Two-loop mass splittings in electroweak multiplets: winos and minimal dark matter

Authors: James McKay, Pat Scott

Abstract: The radiatively-induced splitting of masses in electroweak multiplets is relevant for both collider phenomenology and dark matter. Precision two-loop corrections of $\mathcal{O}$(MeV) to the triplet mass splitting in the wino limit of the minimal supersymmetric standard model can affect particle lifetimes by up to $40\%$. We improve on previous two-loop self-energy calculations for the wino model… ▽ More The radiatively-induced splitting of masses in electroweak multiplets is relevant for both collider phenomenology and dark matter. Precision two-loop corrections of $\mathcal{O}$(MeV) to the triplet mass splitting in the wino limit of the minimal supersymmetric standard model can affect particle lifetimes by up to $40\%$. We improve on previous two-loop self-energy calculations for the wino model by obtaining consistent input parameters to the calculation via two-loop renormalisation-group running, and including the effect of finite light quark masses. We also present the first two-loop calculation of the mass splitting in an electroweak fermionic quintuplet, corresponding to the viable form of minimal dark matter (MDM). We place significant constraints on the lifetimes of the charged and doubly-charged fermions in this model. We find that the two-loop mass splittings in the MDM quintuplet are not constant in the large-mass limit, as might naively be expected from the triplet calculation. This is due to the influence of the additional heavy fermions in loop corrections to the gauge boson propagators. △ Less

Submitted 1 April, 2018; v1 submitted 4 December, 2017; originally announced December 2017.

Comments: 31 pages, 10 figures, 2 Tables

Journal ref: Phys. Rev. D 97, 055049 (2018)

Dark matter theory: Implications and future prospects for Fermi

Authors: Pat Scott

Abstract: I give a brief review of some of the implications of Fermi data for theories of the identity of dark matter, and their combination with data from other complementary probes. I also preview some of the prospects for probing such models with future data. I give a brief review of some of the implications of Fermi data for theories of the identity of dark matter, and their combination with data from other complementary probes. I also preview some of the prospects for probing such models with future data. △ Less

Submitted 6 November, 2017; originally announced November 2017.

Comments: 8 pages, 5 figures. To appear in the proceedings of the 7th International Fermi Symposium, Garmish, Oct 15-20 2017

Neutrino telescope searches for dark matter in the Sun

Authors: Pat Scott

Abstract: I give a brief review of a few recent developments and future directions in the search for dark matter using high-energy neutrinos from the Sun. This includes the ability to recast neutrino telescope limits on nuclear scattering of dark matter to arbitrary new theories, and new calculations of the solar atmospheric background relevant to such searches. I also touch on applications to global search… ▽ More I give a brief review of a few recent developments and future directions in the search for dark matter using high-energy neutrinos from the Sun. This includes the ability to recast neutrino telescope limits on nuclear scattering of dark matter to arbitrary new theories, and new calculations of the solar atmospheric background relevant to such searches. I also touch on applications to global searches for new physics, and prospects for improving searches for asymmetric dark matter in the Sun. △ Less

Submitted 14 October, 2017; originally announced October 2017.

Comments: 7 pages, 4 figures, to appear in the Proceedings of Rencontres du Vietnam: Exploring the Dark Universe, Quy Nhon, Vietnam, July 23-28

Pitfalls of iterative pole mass calculation in electroweak multiplets

Authors: James McKay, Pat Scott, Peter Athron

Abstract: The radiatively-induced mass splitting between components of an electroweak multiplet is typically of order 100 MeV. This is sufficient to endow the charged components with macroscopically-observable lifetimes, and ensure an electrically-neutral dark matter particle. We show that a commonly used iterative procedure to compute radiatively-corrected pole masses can lead to very different mass splitt… ▽ More The radiatively-induced mass splitting between components of an electroweak multiplet is typically of order 100 MeV. This is sufficient to endow the charged components with macroscopically-observable lifetimes, and ensure an electrically-neutral dark matter particle. We show that a commonly used iterative procedure to compute radiatively-corrected pole masses can lead to very different mass splittings than a non-iterative calculation at the same loop order. By estimating the uncertainties of the two one-loop results, we show that the iterative procedure is significantly more sensitive to the choice of renormalisation scale and gauge parameter than the non-iterative method. This can cause the lifetime of the charged component to vary by up to 12 orders of magnitude if iteration is employed. We show that individual pole masses exhibit similar scale-dependence regardless of the procedure, but that the leading scale-dependent terms cancel when computing the mass splitting if and only if the non-iterative procedure is employed. We show that this behaviour persists at two-loop order: the precision of the mass splitting improves in the non-iterative approach, but our results suggest that higher-order corrections do not reduce the uncertainty in the iterative calculation enough to resolve the problem at two-loop order. We conclude that the iterative procedure should not be used for computing pole masses in situations where electroweak mass splittings are phenomenologically relevant. △ Less

Submitted 15 April, 2018; v1 submitted 4 October, 2017; originally announced October 2017.

Comments: 21 pages, 6 figures, submitted to EPJC

Report number: CoEPP-MN-17-19

Journal ref: Eur. Phys. J. Plus 133, 444 (2018)

Comparison of statistical sampling methods with ScannerBit, the GAMBIT scanning module

Authors: The GAMBIT Scanner Workgroup, :, Gregory D. Martinez, James McKay, Ben Farmer, Pat Scott, Elinore Roebber, Antje Putze, Jan Conrad

Abstract: We introduce ScannerBit, the statistics and sampling module of the public, open-source global fitting framework GAMBIT. ScannerBit provides a standardised interface to different sampling algorithms, enabling the use and comparison of multiple computational methods for inferring profile likelihoods, Bayesian posteriors, and other statistical quantities. The current version offers random, grid, rast… ▽ More We introduce ScannerBit, the statistics and sampling module of the public, open-source global fitting framework GAMBIT. ScannerBit provides a standardised interface to different sampling algorithms, enabling the use and comparison of multiple computational methods for inferring profile likelihoods, Bayesian posteriors, and other statistical quantities. The current version offers random, grid, raster, nested sampling, differential evolution, Markov Chain Monte Carlo (MCMC) and ensemble Monte Carlo samplers. We also announce the release of a new standalone differential evolution sampler, Diver, and describe its design, usage and interface to ScannerBit. We subject Diver and three other samplers (the nested sampler MultiNest, the MCMC GreAT, and the native ScannerBit implementation of the ensemble Monte Carlo algorithm T-Walk) to a battery of statistical tests. For this we use a realistic physical likelihood function, based on the scalar singlet model of dark matter. We examine the performance of each sampler as a function of its adjustable settings, and the dimensionality of the sampling problem. We evaluate performance on four metrics: optimality of the best fit found, completeness in exploring the best-fit region, number of likelihood evaluations, and total runtime. For Bayesian posterior estimation at high resolution, T-Walk provides the most accurate and timely mapping of the full parameter space. For profile likelihood analysis in less than about ten dimensions, we find that Diver and MultiNest score similarly in terms of best fit and speed, outperforming GreAT and T-Walk; in ten or more dimensions, Diver substantially outperforms the other three samplers on all metrics. △ Less

Submitted 15 October, 2017; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 51 pages, 25 figures, 2 tables, matches version accepted for publication in EPJC

Report number: gambit-code-2017

Journal ref: Eur. Phys. J. C (2017) 77:761

SpecBit, DecayBit and PrecisionBit: GAMBIT modules for computing mass spectra, particle decay rates and precision observables

Authors: The GAMBIT Models Workgroup, :, Peter Athron, Csaba Balázs, Lars A. Dal, Joakim Edsjö, Ben Farmer, Tomás E. Gonzalo, Anders Kvellestad, James McKay, Antje Putze, Chris Rogan, Pat Scott, Christoph Weniger, Martin White

Abstract: We present the GAMBIT modules SpecBit, DecayBit and PrecisionBit. Together they provide a new framework for linking publicly available spectrum generators, decay codes and other precision observable calculations in a physically and statistically consistent manner. This allows users to automatically run various combinations of existing codes as if they are a single package. The modular design allow… ▽ More We present the GAMBIT modules SpecBit, DecayBit and PrecisionBit. Together they provide a new framework for linking publicly available spectrum generators, decay codes and other precision observable calculations in a physically and statistically consistent manner. This allows users to automatically run various combinations of existing codes as if they are a single package. The modular design allows software packages fulfilling the same role to be exchanged freely at runtime, with the results presented in a common format that can be easily passed to downstream dark matter, collider and flavour codes. These modules constitute an essential part of the broader GAMBIT framework, a major new software package for performing global fits. In this paper we present the observable calculations, data, and likelihood functions implemented in the three modules, as well as the conventions and assumptions used in interfacing them with external codes. We also present 3-BIT-HIT, a command-line utility for computing mass spectra, couplings, decays and precision observables in the MSSM, which shows how the three modules can be easily used independently of GAMBIT. △ Less

Submitted 17 January, 2019; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 67 pages, 9 figures, updated to match version published in EPJC

Report number: CoEPP-MN-17-7, gambit-code-2017

Journal ref: Eur. Phys. J. C (2018) 78: 22

Global fits of GUT-scale SUSY models with GAMBIT

Authors: The GAMBIT Collaboration, Peter Athron, Csaba Balázs, Torsten Bringmann, Andy Buckley, Marcin Chrząszcz, Jan Conrad, Jonathan M. Cornell, Lars A. Dal, Joakim Edsjö, Ben Farmer, Paul Jackson, Abram Krislock, Anders Kvellestad, Farvah Mahmoudi, Gregory D. Martinez, Antje Putze, Are Raklev, Christopher Rogan, Roberto Ruiz de Austri, Aldo Saavedra, Christopher Savage, Pat Scott, Nicola Serra, Christoph Weniger , et al. (1 additional authors not shown)

Abstract: We present the most comprehensive global fits to date of three supersymmetric models motivated by grand unification: the Constrained Minimal Supersymmetric Standard Model (CMSSM), and its Non-Universal Higgs Mass generalisations NUHM1 and NUHM2. We include likelihoods from a number of direct and indirect dark matter searches, a large collection of electroweak precision and flavour observables, dir… ▽ More We present the most comprehensive global fits to date of three supersymmetric models motivated by grand unification: the Constrained Minimal Supersymmetric Standard Model (CMSSM), and its Non-Universal Higgs Mass generalisations NUHM1 and NUHM2. We include likelihoods from a number of direct and indirect dark matter searches, a large collection of electroweak precision and flavour observables, direct searches for supersymmetry at LEP and Runs I and II of the LHC, and constraints from Higgs observables. Our analysis improves on existing results not only in terms of the number of included observables, but also in the level of detail with which we treat them, our sampling techniques for scanning the parameter space, and our treatment of nuisance parameters. We show that stau co-annihilation is now ruled out in the CMSSM at more than 95\% confidence. Stop co-annihilation turns out to be one of the most promising mechanisms for achieving an appropriate relic density of dark matter in all three models, whilst avoiding all other constraints. We find high-likelihood regions of parameter space featuring light stops and charginos, making them potentially detectable in the near future at the LHC. We also show that tonne-scale direct detection will play a largely complementary role, probing large parts of the remaining viable parameter space, including essentially all models with multi-TeV neutralinos. △ Less

Submitted 23 October, 2018; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 50 pages, 21 figures, 7 tables, v2 accepted for publication in EPJC, v3 update Zenodo link

Report number: CoEPP-MN-17-9, gambit-physics-2017

FlavBit: A GAMBIT module for computing flavour observables and likelihoods

Authors: Florian U. Bernlochner, Marcin Chrzaszcz, Lars A. Dal, Ben Farmer, Paul Jackson, Anders Kvellestad, Farvah Mahmoudi, Antje Putze, Christopher Rogan, Pat Scott, Nicola Serra, Christoph Weniger, Martin White

Abstract: Flavour physics observables are excellent probes of new physics up to very high energy scales. Here we present FlavBit, the dedicated flavour physics module of the global-fitting package GAMBIT. FlavBit includes custom implementations of various likelihood routines for a wide range of flavour observables, including detailed uncertainties and correlations associated with LHCb measurements of rare,… ▽ More Flavour physics observables are excellent probes of new physics up to very high energy scales. Here we present FlavBit, the dedicated flavour physics module of the global-fitting package GAMBIT. FlavBit includes custom implementations of various likelihood routines for a wide range of flavour observables, including detailed uncertainties and correlations associated with LHCb measurements of rare, leptonic and semileptonic decays of B and D mesons, kaons and pions. It provides a generalised interface to external theory codes such as SuperIso, allowing users to calculate flavour observables in and beyond the Standard Model, and then test them in detail against all relevant experimental data. We describe FlavBit and its constituent physics in some detail, then give examples from supersymmetry and effective field theory illustrating how it can be used both as a standalone library for flavour physics, and within GAMBIT. △ Less

Submitted 28 November, 2017; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 25 pages, 2 figures, 9 tables. v2: References added

Report number: CERN-TH-2017-167, NORDITA 2017-077, gambit-code-2017

Journal ref: Eur.Phys.J. C77 (2017) no.11, 786

Status of the scalar singlet dark matter model

Authors: The GAMBIT Collaboration, Peter Athron, Csaba Balázs, Torsten Bringmann, Andy Buckley, Marcin Chrząszcz, Jan Conrad, Jonathan M. Cornell, Lars A. Dal, Joakim Edsjö, Ben Farmer, Paul Jackson, Felix Kahlhoefer, Abram Krislock, Anders Kvellestad, James McKay, Farvah Mahmoudi, Gregory D. Martinez, Antje Putze, Are Raklev, Christopher Rogan, Aldo Saavedra, Christopher Savage, Pat Scott, Nicola Serra , et al. (2 additional authors not shown)

Abstract: One of the simplest viable models for dark matter is an additional neutral scalar, stabilised by a $\mathbb{Z}_2$ symmetry. Using the GAMBIT package and combining results from four independent samplers, we present Bayesian and frequentist global fits of this model. We vary the singlet mass and coupling along with 13 nuisance parameters, including nuclear uncertainties relevant for direct detection… ▽ More One of the simplest viable models for dark matter is an additional neutral scalar, stabilised by a $\mathbb{Z}_2$ symmetry. Using the GAMBIT package and combining results from four independent samplers, we present Bayesian and frequentist global fits of this model. We vary the singlet mass and coupling along with 13 nuisance parameters, including nuclear uncertainties relevant for direct detection, the local dark matter density, and selected quark masses and couplings. We include the dark matter relic density measured by Planck, direct searches with LUX, PandaX, SuperCDMS and XENON100, limits on invisible Higgs decays from the Large Hadron Collider, searches for high-energy neutrinos from dark matter annihilation in the Sun with IceCube, and searches for gamma rays from annihilation in dwarf galaxies with the Fermi-LAT. Viable solutions remain at couplings of order unity, for singlet masses between the Higgs mass and about 300 GeV, and at masses above $\sim$1 TeV. Only in the latter case can the scalar singlet constitute all of dark matter. Frequentist analysis shows that the low-mass resonance region, where the singlet is about half the mass of the Higgs, can also account for all of dark matter, and remains viable. However, Bayesian considerations show this region to be rather fine-tuned. △ Less

Submitted 19 October, 2018; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 19 pages, 5 figures, matches published version. v3 updates the Zenodo URL for supplementary data (available at https://doi.org/10.5281/zenodo.801510)

Report number: CoEPP-MN-17-10, gambit-physics-2017

Journal ref: Eur. Phys. J. C 77, 568 (2017)

DarkBit: A GAMBIT module for computing dark matter observables and likelihoods

Authors: Torsten Bringmann, Jan Conrad, Jonathan M. Cornell, Lars A. Dal, Joakim Edsjö, Ben Farmer, Felix Kahlhoefer, Anders Kvellestad, Antje Putze, Christopher Savage, Pat Scott, Christoph Weniger, Martin White, Sebastian Wild

Abstract: We introduce DarkBit, an advanced software code for computing dark matter constraints on various extensions to the Standard Model of particle physics, comprising both new native code and interfaces to external packages. This release includes a dedicated signal yield calculator for gamma-ray observations, which significantly extends current tools by implementing a cascade decay Monte Carlo, as well… ▽ More We introduce DarkBit, an advanced software code for computing dark matter constraints on various extensions to the Standard Model of particle physics, comprising both new native code and interfaces to external packages. This release includes a dedicated signal yield calculator for gamma-ray observations, which significantly extends current tools by implementing a cascade decay Monte Carlo, as well as a dedicated likelihood calculator for current and future experiments (gamlike). This provides a general solution for studying complex particle physics models that predict dark matter annihilation to a multitude of final states. We also supply a direct detection package that models a large range of direct detection experiments (DDcalc), and provides the corresponding likelihoods for arbitrary combinations of spin-independent and spin-dependent scattering processes. Finally, we provide custom relic density routines along with interfaces to DarkSUSY, micrOMEGAs, and the neutrino telescope likelihood package nuLike. DarkBit is written in the framework of the Global And Modular Beyond the Standard Model Inference Tool (GAMBIT), providing seamless integration into a comprehensive statistical fitting framework that allows users to explore new models with both particle and astrophysics constraints, and a consistent treatment of systematic uncertainties. In this paper we describe its main functionality, provide a guide to getting started quickly, and show illustrative examples for results obtained with DarkBit (both as a standalone tool and as a GAMBIT module). This includes a quantitative comparison between two of the main dark matter codes (DarkSUSY and micrOMEGAs), and application of DarkBit's advanced direct and indirect detection routines to a simple effective dark matter model. △ Less

Submitted 8 January, 2018; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 53 pages, 9 figures, 25 tables. v2: Updated to reflect new functionality in version 1.1.0, including the addition of Xenon1T and PICO-60 likelihoods. Minor corrections and clarifications throughout. Matches published version

Report number: DESY-17-235, NORDITA-2017-076, gambit-code-2017

Journal ref: Eur.Phys.J. C77 (2017) no.12, 831

ColliderBit: a GAMBIT module for the calculation of high-energy collider observables and likelihoods

Authors: Csaba Balázs, Andy Buckley, Lars A. Dal, Ben Farmer, Paul Jackson, Abram Krislock, Anders Kvellestad, Daniel Murnane, Antje Putze, Are Raklev, Christopher Rogan, Aldo Saavedra, Pat Scott, Christoph Weniger, Martin White

Abstract: We describe ColliderBit, a new code for the calculation of high energy collider observables in theories of physics beyond the Standard Model (BSM). ColliderBit features a generic interface to BSM models, a unique parallelised Monte Carlo event generation scheme suitable for large-scale supercomputer applications, and a number of LHC analyses, covering a reasonable range of the BSM signatures curre… ▽ More We describe ColliderBit, a new code for the calculation of high energy collider observables in theories of physics beyond the Standard Model (BSM). ColliderBit features a generic interface to BSM models, a unique parallelised Monte Carlo event generation scheme suitable for large-scale supercomputer applications, and a number of LHC analyses, covering a reasonable range of the BSM signatures currently sought by ATLAS and CMS. ColliderBit also calculates likelihoods for Higgs sector observables, and LEP searches for BSM particles. These features are provided by a combination of new code unique to ColliderBit, and interfaces to existing state-of-the-art public codes. ColliderBit is both an important part of the GAMBIT framework for BSM inference, and a standalone tool for efficiently applying collider constraints to theories of new physics. △ Less

Submitted 2 April, 2019; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 31 pages, 7 figures, 17 tables. Replacement version accepted by EPJC

Report number: gambit-code-2017

A global fit of the MSSM with GAMBIT

Authors: The GAMBIT Collaboration, Peter Athron, Csaba Balázs, Torsten Bringmann, Andy Buckley, Marcin Chrząszcz, Jan Conrad, Jonathan M. Cornell, Lars A. Dal, Joakim Edsjö, Ben Farmer, Paul Jackson, Abram Krislock, Anders Kvellestad, Farvah Mahmoudi, Gregory D. Martinez, Antje Putze, Are Raklev, Christopher Rogan, Aldo Saavedra, Christopher Savage, Pat Scott, Nicola Serra, Christoph Weniger, Martin White

Abstract: We study the seven-dimensional Minimal Supersymmetric Standard Model (MSSM7) with the new GAMBIT software framework, with all parameters defined at the weak scale. Our analysis significantly extends previous weak-scale, phenomenological MSSM fits, by adding more and newer experimental analyses, improving the accuracy and detail of theoretical predictions, including dominant uncertainties from the… ▽ More We study the seven-dimensional Minimal Supersymmetric Standard Model (MSSM7) with the new GAMBIT software framework, with all parameters defined at the weak scale. Our analysis significantly extends previous weak-scale, phenomenological MSSM fits, by adding more and newer experimental analyses, improving the accuracy and detail of theoretical predictions, including dominant uncertainties from the Standard Model, the Galactic dark matter halo and the quark content of the nucleon, and employing novel and highly-efficient statistical sampling methods to scan the parameter space. We find regions of the MSSM7 that exhibit co-annihilation of neutralinos with charginos, stops and sbottoms, as well as models that undergo resonant annihilation via both light and heavy Higgs funnels. We find high-likelihood models with light charginos, stops and sbottoms that have the potential to be within the future reach of the LHC. Large parts of our preferred parameter regions will also be accessible to the next generation of direct and indirect dark matter searches, making prospects for discovery in the near future rather good. △ Less

Submitted 22 October, 2018; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 31 pages, 14 figures; v2 matches version accepted by EPJC; v3 has corrected link to supplementary data on Zenodo

Report number: CERN-TH-2017-169, CoEPP-MN-17-11, NORDITA 2017-081, gambit-physics-2017

Journal ref: Eur.Phys.J. C77 (2017) no.12, 879

GAMBIT: The Global and Modular Beyond-the-Standard-Model Inference Tool

Authors: The GAMBIT Collaboration, Peter Athron, Csaba Balazs, Torsten Bringmann, Andy Buckley, Marcin Chrząszcz, Jan Conrad, Jonathan M. Cornell, Lars A. Dal, Hugh Dickinson, Joakim Edsjö, Ben Farmer, Tomás E. Gonzalo, Paul Jackson, Abram Krislock, Anders Kvellestad, Johan Lundberg, James McKay, Farvah Mahmoudi, Gregory D. Martinez, Antje Putze, Are Raklev, Joachim Ripken, Christopher Rogan, Aldo Saavedra , et al. (7 additional authors not shown)

Abstract: We describe the open-source global fitting package GAMBIT: the Global And Modular Beyond-the-Standard-Model Inference Tool. GAMBIT combines extensive calculations of observables and likelihoods in particle and astroparticle physics with a hierarchical model database, advanced tools for automatically building analyses of essentially any model, a flexible and powerful system for interfacing to exter… ▽ More We describe the open-source global fitting package GAMBIT: the Global And Modular Beyond-the-Standard-Model Inference Tool. GAMBIT combines extensive calculations of observables and likelihoods in particle and astroparticle physics with a hierarchical model database, advanced tools for automatically building analyses of essentially any model, a flexible and powerful system for interfacing to external codes, a suite of different statistical methods and parameter scanning algorithms, and a host of other utilities designed to make scans faster, safer and more easily-extendible than in the past. Here we give a detailed description of the framework, its design and motivation, and the current models and other specific components presently implemented in GAMBIT. Accompanying papers deal with individual modules and present first GAMBIT results. GAMBIT can be downloaded from gambit.hepforge.org. △ Less

Submitted 3 November, 2017; v1 submitted 22 May, 2017; originally announced May 2017.

Comments: 84 pages, 8 Figures. Code available at http://gambit.hepforge.org. v2: Main paper now matches version accepted by EPJC. This version also adds an addendum submitted to EPJC on Mathematica support in GAMBIT v1.1

Report number: CERN-TH-2017-166, CoEPP-MN-17-6, NORDITA 2017-074, DESY 17-236, gambit-code-2017

Evaporation and scattering of momentum- and velocity-dependent dark matter in the Sun

Authors: Giorgio Busoni, Andrea De Simone, Pat Scott, Aaron C. Vincent

Abstract: Dark matter with momentum- or velocity-dependent interactions with nuclei has shown significant promise for explaining the so-called Solar Abundance Problem, a longstanding discrepancy between solar spectroscopy and helioseismology. The best-fit models are all rather light, typically with masses in the range of 3-5 GeV. This is exactly the mass range where dark matter evaporation from the Sun can… ▽ More Dark matter with momentum- or velocity-dependent interactions with nuclei has shown significant promise for explaining the so-called Solar Abundance Problem, a longstanding discrepancy between solar spectroscopy and helioseismology. The best-fit models are all rather light, typically with masses in the range of 3-5 GeV. This is exactly the mass range where dark matter evaporation from the Sun can be important, but to date no detailed calculation of the evaporation of such models has been performed. Here we carry out this calculation, for the first time including arbitrary velocity- and momentum-dependent interactions, thermal effects, and a completely general treatment valid from the optically thin limit all the way through to the optically thick regime. We find that depending on the dark matter mass, interaction strength and type, the mass below which evaporation is relevant can vary from 1 to 4 GeV. This has the effect of weakening some of the better-fitting solutions to the Solar Abundance Problem, but also improving a number of others. As a by-product, we also provide an improved derivation of the capture rate that takes into account thermal and optical depth effects, allowing the standard result to be smoothly matched to the well-known saturation limit. △ Less

Submitted 24 October, 2017; v1 submitted 22 March, 2017; originally announced March 2017.

Comments: 32 pages including appendices; 10 figures. References added and minor corrections made to match published version

Journal ref: JCAP10(2017)037

Dark matter substructure cannot explain properties of the Fermi Galactic Centre excess

Authors: Hamish A. Clark, Pat Scott, Roberto Trotta, Geraint F. Lewis

Abstract: An excess of gamma rays has been identified at the centre of the Milky Way, and annihilation of dark matter has been posited as a potential source. This hypothesis faces significant challenges: difficulty characterizing astrophysical backgrounds, the need for a non-trivial adiabatic contraction of the inner part of the Milky Way's dark matter halo, and recent observations of photon clustering, whi… ▽ More An excess of gamma rays has been identified at the centre of the Milky Way, and annihilation of dark matter has been posited as a potential source. This hypothesis faces significant challenges: difficulty characterizing astrophysical backgrounds, the need for a non-trivial adiabatic contraction of the inner part of the Milky Way's dark matter halo, and recent observations of photon clustering, which suggest that the majority of the excess is due to unresolved point sources. Here we point out that the apparent point-like nature of the emission rules out the dark matter interpretation of the excess entirely. Attempting to model the emission with dark matter point sources either worsens the problem with the inner slope, requires an unrealistically large minihalo fraction toward the Galactic Centre, or overproduces the observed emission at higher latitudes. △ Less

Submitted 2 September, 2018; v1 submitted 5 December, 2016; originally announced December 2016.

Comments: 14 pages, 4 figures

Journal ref: JCAP 07 (2018) 060

Heating of galactic gas by dark matter annihilation in ultracompact minihalos

Authors: Hamish A. Clark, Nikolas Iwanus, Pascal J. Elahi, Geraint F. Lewis, Pat Scott

Abstract: The existence of substructure in halos of annihilating dark matter would be expected to substantially boost the rate at which annihilation occurs. Ultracompact minihalos of dark matter (UCMHs) are one of the more extreme examples of this. The boosted annihilation can inject significant amounts of energy into the gas of a galaxy over its lifetime. Here we determine the impact of the boost factor fr… ▽ More The existence of substructure in halos of annihilating dark matter would be expected to substantially boost the rate at which annihilation occurs. Ultracompact minihalos of dark matter (UCMHs) are one of the more extreme examples of this. The boosted annihilation can inject significant amounts of energy into the gas of a galaxy over its lifetime. Here we determine the impact of the boost factor from UCMH substructure on the heating of galactic gas in a Milky Way-type galaxy, by means of N-body simulation. If $1\%$ of the dark matter exists as UCMHs, the corresponding boost factor can be of order $10^5$. For reasonable values of the relevant parameters (annihilation cross section $3\times10^{-26} ~\textrm{cm}^3~ \textrm{s}^{-1}$, dark matter mass 100 GeV, 10% heating efficiency), we show that the presence of UCMHs at the 0.1% level would inject enough energy to eject significant amounts of gas from the halo, potentially preventing star formation within $\sim$1 kpc of the halo centre. △ Less

Submitted 25 May, 2017; v1 submitted 25 November, 2016; originally announced November 2016.

Comments: 14 pages, 3 figures

Journal ref: JCAP 05 (2017) 048

Effect of electromagnetic dipole dark matter on energy transport in the solar interior

Authors: Ben Geytenbeek, Soumya Rao, Pat Scott, Aldo Serenelli, Aaron C Vincent, Martin White, Anthony G Williams

Abstract: In recent years, a revised set of solar abundances has led to a discrepancy in the sound-speed profile between helioseismology and theoretical solar models. Conventional solutions require additional mechanisms for energy transport within the Sun. Vincent et al. have recently suggested that dark matter with a momentum or velocity dependent cross section could provide a solution. In this work, we co… ▽ More In recent years, a revised set of solar abundances has led to a discrepancy in the sound-speed profile between helioseismology and theoretical solar models. Conventional solutions require additional mechanisms for energy transport within the Sun. Vincent et al. have recently suggested that dark matter with a momentum or velocity dependent cross section could provide a solution. In this work, we consider three models of dark matter with such cross sections and their effect on the stellar structure. In particular, the three models incorporate dark matter particles interacting through an electromagnetic dipole moment: an electric dipole, a magnetic dipole or an anapole. Each model is implemented in the \texttt{DarkStec} stellar evolution program, which incorporates the effects of dark matter capture and heat transport within the solar interior. We show that dark matter with an anapole moment of $\sim1\mathrm{GeV}^{-2}$ or magnetic dipole moment of $\sim10^{-3}μ_p$ can improve the sound-speed profile, small frequency separations and convective zone radius with respect to the Standard Solar Model. However, the required dipole moments are strongly excluded by direct detection experiments. △ Less

Submitted 28 February, 2017; v1 submitted 21 October, 2016; originally announced October 2016.

Comments: 36 pages, 11 figures

Report number: ADP-16-33/T989; IPPP/09/81

Towards the next generation of simplified Dark Matter models

Authors: Andreas Albert, Martin Bauer, Oliver Buchmueller, Jim Brooke, David G. Cerdeno, Matthew Citron, Gavin Davies, Annapaola de Cosa, Albert De Roeck, Andrea De Simone, Tristan Du Pree, John Ellis, Henning Flaecher, Malcolm Fairbairn, Alexander Grohsjean, Kristian Hahn, Ulrich Haisch, Philip C. Harris, Valentin V. Khoze, Greg Landsberg, Christopher McCabe, Bjoern Penning, Veronica Sanz, Christian Schwanenberger, Pat Scott , et al. (1 additional authors not shown)

Abstract: This White Paper is an input to the ongoing discussion about the extension and refinement of simplified Dark Matter (DM) models. Based on two concrete examples, we show how existing simplified DM models (SDMM) can be extended to provide a more accurate and comprehensive framework to interpret and characterise collider searches. In the first example we extend the canonical SDMM with a scalar mediat… ▽ More This White Paper is an input to the ongoing discussion about the extension and refinement of simplified Dark Matter (DM) models. Based on two concrete examples, we show how existing simplified DM models (SDMM) can be extended to provide a more accurate and comprehensive framework to interpret and characterise collider searches. In the first example we extend the canonical SDMM with a scalar mediator to include mixing with the Higgs boson. We show that this approach not only provides a better description of the underlying kinematic properties that a complete model would possess, but also offers the option of using this more realistic class of scalar mixing models to compare and combine consistently searches based on different experimental signatures. The second example outlines how a new physics signal observed in a visible channel can be connected to DM by extending a simplified model including effective couplings. This discovery scenario uses the recently observed excess in the high-mass diphoton searches of ATLAS and CMS for a case study to show that such a pragmatic approach can aid the experimental search programme to verify/falsify a potential signal and to study its underlying nature. In the next part of the White Paper we outline other interesting options for SDMM that could be studied in more detail in the future. Finally, we discuss important aspects of supersymmetric models for DM and how these could help to develop of more complete SDMM. △ Less

Submitted 25 February, 2017; v1 submitted 22 July, 2016; originally announced July 2016.

Updated constraints on velocity and momentum-dependent asymmetric dark matter

Authors: Aaron C. Vincent, Pat Scott, Aldo Serenelli

Abstract: We present updated constraints on dark matter models with momentum-dependent or velocity-dependent interactions with nuclei, based on direct detection and solar physics. We improve our previous treatment of energy transport in the solar interior by dark matter scattering, leading to significant changes in fits to many observables. Based on solar physics alone, DM with a spin-independent $q^{4}$ co… ▽ More We present updated constraints on dark matter models with momentum-dependent or velocity-dependent interactions with nuclei, based on direct detection and solar physics. We improve our previous treatment of energy transport in the solar interior by dark matter scattering, leading to significant changes in fits to many observables. Based on solar physics alone, DM with a spin-independent $q^{4}$ coupling provides the best fit to data, and a statistically satisfactory solution to the solar abundance problem. Once direct detection limits are accounted for however, the best solution is spin-dependent $v^2$ scattering with a reference cross-section of 10$^{-35}$ cm$^2$ (at a reference velocity of $v_0=220$ km s$^{-1}$), and a dark matter mass of about 5 GeV. △ Less

Submitted 24 October, 2016; v1 submitted 20 May, 2016; originally announced May 2016.

Comments: 34 pages, 18 figures. Accepted in JCAP. Ancillary file likelihood_solarDM.dat contains observables and chi-squared values for each model studied

Report number: IPPP/16/45

Improved limits on dark matter annihilation in the Sun with the 79-string IceCube detector and implications for supersymmetry

Authors: IceCube Collaboration, M. G. Aartsen, K. Abraham, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, D. Altmann, T. Anderson, I. Ansseau, G. Anton, M. Archinger, C. Arguelles, T. C. Arlen, J. Auffenberg, X. Bai, S. W. Barwick, V. Baum, R. Bay, J. J. Beatty, J. Becker Tjus, K. -H. Becker, E. Beiser, S. BenZvi , et al. (293 additional authors not shown)

Abstract: We present an improved event-level likelihood formalism for including neutrino telescope data in global fits to new physics. We derive limits on spin-dependent dark matter-proton scattering by employing the new formalism in a re-analysis of data from the 79-string IceCube search for dark matter annihilation in the Sun, including explicit energy information for each event. The new analysis excludes… ▽ More We present an improved event-level likelihood formalism for including neutrino telescope data in global fits to new physics. We derive limits on spin-dependent dark matter-proton scattering by employing the new formalism in a re-analysis of data from the 79-string IceCube search for dark matter annihilation in the Sun, including explicit energy information for each event. The new analysis excludes a number of models in the weak-scale minimal supersymmetric standard model (MSSM) for the first time. This work is accompanied by the public release of the 79-string IceCube data, as well as an associated computer code for applying the new likelihood to arbitrary dark matter models. △ Less

Submitted 23 March, 2016; v1 submitted 4 January, 2016; originally announced January 2016.

Comments: 24 pages, 8 figs, 1 table. Contact authors: Pat Scott & Matthias Danninger. Likelihood tool available at http://nulike.hepforge.org. v2: small updates to address JCAP referee report

Journal ref: JCAP 04 (2016) 022

Combined analysis of effective Higgs portal dark matter models

Authors: Ankit Beniwal, Filip Rajec, Christopher Savage, Pat Scott, Christoph Weniger, Martin White, Anthony G. Williams

Abstract: We combine and extend the analyses of effective scalar, vector, Majorana and Dirac fermion Higgs portal models of dark matter (DM), in which DM couples to the Standard Model (SM) Higgs boson via an operator of the form $\mathcal{O}_{\textrm{DM}}\, H^\dagger H$. For the fermion models, we take an admixture of scalar $\overlineψ ψ$ and pseudoscalar $\overlineψ iγ_5 ψ$ interaction terms. For each mod… ▽ More We combine and extend the analyses of effective scalar, vector, Majorana and Dirac fermion Higgs portal models of dark matter (DM), in which DM couples to the Standard Model (SM) Higgs boson via an operator of the form $\mathcal{O}_{\textrm{DM}}\, H^\dagger H$. For the fermion models, we take an admixture of scalar $\overlineψ ψ$ and pseudoscalar $\overlineψ iγ_5 ψ$ interaction terms. For each model, we apply constraints on the parameter space based on the Planck measured DM relic density and the LHC limits on the Higgs invisible branching ratio. For the first time, we perform a consistent study of the indirect detection prospects for these models based on the WMAP7/Planck observations of the cosmic microwave background, a combined analysis of 15 dwarf spheroidal galaxies by Fermi-LAT and the upcoming Cherenkov Telescope Array (CTA). We also perform a correct treatment of the momentum-dependent direct search cross section that arises from the pseudoscalar interaction term in the fermionic DM theories. We find, in line with previous studies, that current and future direct search experiments such as LUX and XENON1T can exclude much of the parameter space, and we demonstrate that a joint observation in both indirect and direct searches is possible for high mass weakly interacting massive particles. In the case of a pure pseudoscalar interaction of a fermionic DM candidate, future gamma-ray searches are the only class of experiment capable of probing the high mass range of the theory. △ Less

Submitted 14 June, 2016; v1 submitted 20 December, 2015; originally announced December 2015.

Comments: 53 pages, 16 figures, REVTeX-4.1 processed with BibTeX and pdfLaTeX. v2: added references; submitted to Phys. Rev. D. v3: added references and corrected few typos; matches the version accepted for publication in Phys. Rev. D. v4: matches the version published in Phys. Rev. D

Report number: ADP-15-52/T954

Journal ref: Phys. Rev. D 93, 115016 (2016)