<p>Dark matter particles with a mass around 1 eV can decay into near-infrared photons. Utilizing available public blank sky observations from the NIRSpec IFU on the James Webb Space Telescope (JWST), we search for a narrow emission line due to decaying dark matter and derive leading constraints in the mass range 0.8–3 eV on the decay rate to photons, and more specifically, on the axion-photon coupling for the case of axionlike particles. We exclude <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo>&lt;</mo><mn>3.5</mn><mo>×</mo><msup><mn>10</mn><mn>26</mn></msup><mtext> </mtext><mtext> </mtext><mi mathvariant="normal">s</mi></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>DM</mi></mrow></msub><mo>≃</mo><mn>0.8</mn><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></math> and, in the case of axions, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>a</mi><mi>γ</mi><mi>γ</mi></mrow></msub><mo>&gt;</mo><mn>1.3</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>≃</mo><mn>2.2</mn><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></math>. Our results do not rely on dedicated observations, rather we use blank sky observations intended for sky subtraction, and thus our reach may be automatically strengthened as JWST continues to observe.</p>

United States

Ryan Janish

Elena Pinetti

Hunting Dark Matter Lines in the Infrared Background with the James Webb Space Telescope

In this work we present a simple extension of the Standard Model that contains, as the only new physics component, a massive spin-one matter field in the adjoint representation of <math><mi>S</mi><mi>U</mi><mo>(</mo><mn>2</mn><msub><mo>)</mo><mi>L</mi></msub></math>. In order to be consistent with perturbative unitarity, the vector field must be odd under a <math><msub><mi>Z</mi><mn>2</mn></msub></math> symmetry. Radiative corrections make the neutral component of the triplet (<math><msup><mi>V</mi><mn>0</mn></msup></math>) slightly lighter than the charged ones. We show that <math><msup><mi>V</mi><mn>0</mn></msup></math> can be the dark matter particle while satisfying all current bounds if it has a mass between 2.8 and 3.8 TeV. We present the current limit on the model parameter space from highly complementary experimental constraints, including dark matter relic density measurement, dark matter direct and indirect detection searches, LHC data on Higgs couplings to photons and LHC data on disappearing track searches. We also show that the two-dimensional parameter space can be fully covered by disappearing track searches at a future 100 TeV hadron collider, which will probe, in particular, the whole mass range relevant for dark matter, thus giving an opportunity to discover or exclude the model.

United Kingdom

Alexander Belyaev

France

Giacomo Cacciapaglia

James McKay

Chile

Dixon Marin

Alfonso R. Zerwekh

Minimal spin-one isotriplet dark matter

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 $$\mathbb {Z}_2$$ <math><msub><mi>Z</mi><mn>2</mn></msub></math>  or a $$\mathbb {Z}_3$$ <math><msub><mi>Z</mi><mn>3</mn></msub></math>  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 1–2 TeV and a spin-independent nuclear scattering cross-section around $$10^{-45}\,\hbox {cm}^2$$ <math><mrow><msup><mn>10</mn><mrow><mo>-</mo><mn>45</mn></mrow></msup><mspace width="0.166667em"></mspace><msup><mtext>cm</mtext><mn>2</mn></msup></mrow></math> .

Australia

Peter Athron

Canada

Jonathan Cornell

Germany

Felix Kahlhoefer

Pat Scott

Sebastian Wild

Impact of vacuum stability, perturbativity and XENON1T on global fits of $$\mathbb {Z}_2$$ <math><msub><mi>Z</mi><mn>2</mn></msub></math>  and $$\mathbb {Z}_3$$ <math><msub><mi>Z</mi><mn>3</mn></msub></math>  scalar singlet dark matter

The radiatively-induced splitting of masses in electroweak multiplets is relevant for both collider phenomenology and dark matter. Precision two-loop corrections of <math><mrow><mi>O</mi><mo>(</mo><mi>MeV</mi><mo>)</mo></mrow></math> 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 renormalization-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.

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

In Ref. (GAMBIT Collaboration: Athron et. al., Eur. Phys. J. C. arXiv:1705.07908 , 2017 ) we introduced the global-fitting framework GAMBIT. In this addendum, we describe a new minor version increment of this package. GAMBIT1.1 includes full support for Mathematica backends, which we describe in some detail here. As an example, we backend SUSYHD Â (Vega and Villadoro, JHEP 07:159, 2015 ), which calculates the mass of the Higgs boson in the MSSM from effective field theory. We also describe updated likelihoods in PrecisionBit and DarkBit, and updated decay data included in DecayBit.

Csaba Balazs

Norway

Torsten Bringmann

Andy Buckley

Switzerland

Poland

Marcin Chrząszcz

Sweden

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

CERN

Farvah Mahmoudi

Gregory D. Martinez

Antje Putze

Are Raklev

Joachim Ripken

Christopher Rogan

Aldo Saavedra

Christopher Savage

South Korea

Seon-Hee Seo

Nicola Serra

Netherlands

Christoph Weniger

Martin White

GAMBIT: the global and modular beyond-the-standard-model inference tool

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 easily be 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 easily be used independently of GAMBIT.

Csaba Balázs

Chris Rogan

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

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 .

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.

Elinore Roebber

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

One of the simplest viable models for dark matter is an additional neutral scalar, stabilised by a Z2 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 300Â GeV, and at masses above â¼ 1Â 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.

Status of the scalar singlet dark matter model