Publications
705 results found
Bertone G, Buchmueller OL, Cole PS, 2023, Perspectives on fundamental cosmology from Low Earth Orbit and the Moon, npj Microgravity, Vol: 9
The next generation of space-based experiments will go hunting for answers to cosmology’s key open questions which revolve around inflation, dark matter and dark energy. Low earth orbit and lunar missions within the European Space Agency’s Human and Robotic Exploration programme can push our knowledge forward in all of these three fields. A radio interferometer on the Moon, a cold atom interferometer in low earth orbit and a gravitational wave interferometer on the Moon are highlighted as the most fruitful missions to plan and execute in the mid-term.
Alonso I, Alpigiani C, Altschul B, et al., 2022, Cold atoms in space: community workshop summary and proposed road-map, EPJ QUANTUM TECHNOLOGY, Vol: 9, ISSN: 2662-4400
AbdusSalam SS, Agocs FJ, Allanach BC, et al., 2022, Simple and statistically sound recommendations for analysing physical theories, REPORTS ON PROGRESS IN PHYSICS, Vol: 85, ISSN: 0034-4885
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- Citations: 4
Badurina L, Buchmueller O, Ellis J, et al., 2022, Prospective sensitivities of atom interferometers to gravitational waves and ultralight dark matter, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 380, ISSN: 1364-503X
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- Citations: 15
Bertoldi A, Bongs K, Bouyer P, et al., 2021, AEDGE: Atomic experiment for dark matter and gravity exploration in space, EXPERIMENTAL ASTRONOMY, Vol: 51, Pages: 1417-1426, ISSN: 0922-6435
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- Citations: 6
Alimena J, Beacham J, Borsato M, et al., 2020, Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider, JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS, Vol: 47, ISSN: 0954-3899
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- Citations: 93
Zyla PA, Barnett RM, Beringer J, et al., 2020, Review of particle physics, Progress of Theoretical and Experimental Physics, Vol: 2020, Pages: 1-2093, ISSN: 0033-068X
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,324 new measurements from 878 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 120 reviews are many that are new or heavily revised, including a new review on High Energy Soft QCD and Diffraction and one on the Determination of CKM Angles from B Hadrons.The Review is divided into two volumes. Volume 1 includes the Summary Tables and 98 review articles. Volume 2 consists of the Particle Listings and contains also 22 reviews that address specific aspects of the data presented in the Listings.The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print and as a web version optimized for use on phones as well as an Android app.
Badurina L, Bentine E, Blas D, et al., 2020, AION: an atom interferometer observatory and network, JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, ISSN: 1475-7516
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- Citations: 107
Sirunyan AM, Tumasyan A, Adam W, et al., 2020, A search for the standard model Higgs boson decaying to charm quarks, The Journal of High Energy Physics, Vol: 2020, Pages: 1-54, ISSN: 1029-8479
A direct search for the standard model Higgs boson, H, produced in association with a vector boson, V (W or Z), and decaying to a charm quark pair is presented. The search uses a data set of proton-proton collisions corresponding to an integrated luminosity of 35.9 fb−1, collected by the CMS experiment at the LHC in 2016, at a centre-of-mass energy of 13 TeV. The search is carried out in mutually exclusive channels targeting specific decays of the vector bosons: W → ℓν, Z → ℓℓ, and Z → νν, where ℓ is an electron or a muon. To fully exploit the topology of the H boson decay, two strategies are followed. In the first one, targeting lower vector boson transverse momentum, the H boson candidate is reconstructed via two resolved jets arising from the two charm quarks from the H boson decay. A second strategy identifies the case where the two charm quark jets from the H boson decay merge to form a single jet, which generally only occurs when the vector boson has higher transverse momentum. Both strategies make use of novel methods for charm jet identification, while jet substructure techniques are also exploited to suppress the background in the merged-jet topology. The two analyses are combined to yield a 95% confidence level observed (expected) upper limit on the cross section σ(VH)B(H→cc¯¯) of 4.5 (2.4+1.0−0.7) pb, corresponding to 70 (37) times the standard model prediction.
El-Neaj YA, Alpigiani C, Amairi-Pyka S, et al., 2020, AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space, EPJ QUANTUM TECHNOLOGY, Vol: 7, ISSN: 2662-4400
Abercrombie D, Akchurin N, Akilli E, et al., 2020, Dark Matter benchmark models for early LHC Run-2 Searches: Report of the ATLAS/CMS Dark Matter Forum, PHYSICS OF THE DARK UNIVERSE, Vol: 27, ISSN: 2212-6864
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- Citations: 87
Boveia A, Buchmueller O, Busoni G, et al., 2020, Recommendations on presenting LHC searches for missing transverse energy signals using simplified s-channel models of dark matter, PHYSICS OF THE DARK UNIVERSE, Vol: 27, ISSN: 2212-6864
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- Citations: 35
Albert A, Backovic M, Boveia A, et al., 2019, Recommendations of the LHC Dark Matter Working Group: Comparing LHC searches for dark matter mediators in visible and invisible decay channels and calculations of the thermal relic density, PHYSICS OF THE DARK UNIVERSE, Vol: 26, ISSN: 2212-6864
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- Citations: 24
Bagnaschi E, Costa JC, Sakurai K, et al., 2019, Global analysis of dark matter simplified models with leptophobic spin-one mediators using MasterCode, EUROPEAN PHYSICAL JOURNAL C, Vol: 79, ISSN: 1434-6044
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- Citations: 10
Tanabashi M, Grp PD, Hagiwara K, et al., 2018, Review of Particle Physics, Physical Review D, Vol: 98, ISSN: 2470-0010
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,873new measurements from 758 papers, we list, evaluate, and average measured properties of gauge bosons and therecently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypotheticalparticles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and searchlimits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as HiggsBoson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology,Particle Detectors, Colliders, Probability and Statistics. Among the 118 reviews are many that are new or heavilyrevised, including a new review on Neutrinos in Cosmology.Starting with this edition, the Review is divided into two volumes. Volume 1 includes the Summary Tablesand all review articles. Volume 2 consists of the Particle Listings. Review articles that were previously part of theListings are now included in volume 1.The complete Review (both volumes) is published online on the website of the Particle Data Group(http://pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Bookletwith the Summary Tables and essential tables, figures, and equations from selected review articles is also available.
Sirunyan AM, Tumasyan A, Adam W, et al., 2018, Search for decays of stopped exotic long-lived particles produced in proton-proton collisions at root s=13 TeV, The Journal of High Energy Physics, Pages: 1-47, ISSN: 1029-8479
A search is presented for the decays of heavy exotic long-lived particles (LLPs) that are produced in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC and come to rest in the CMS detector. Their decays would be visible during periods of time well separated from proton-proton collisions. Two decay scenarios of stopped LLPs are explored: a hadronic decay detected in the calorimeter and a decay into muons detected in the muon system. The calorimeter (muon) search covers a period of sensitivity totaling 721 (744) hours in 38.6 (39.0) fb−1 of data collected by the CMS detector in 2015 and 2016. The results are interpreted in several scenarios that predict LLPs. Production cross section limits are set as a function of the mean proper lifetime and the mass of the LLPs, for lifetimes between 100 ns and 10 days. These are the most stringent limits to date on the mass of hadronically decaying stopped LLPs, and this is the first search at the LHC for stopped LLPs that decay to muons.
Sirunyan AM, Tumasyan A, Adam W, et al., 2018, Search for decays of stopped exotic long-lived particles produced in proton-proton collisions at √s=13 TeV, Journal of High Energy Physics, Vol: 2018, ISSN: 1126-6708
© 2018, The Author(s). A search is presented for the decays of heavy exotic long-lived particles (LLPs) that are produced in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC and come to rest in the CMS detector. Their decays would be visible during periods of time well separated from proton-proton collisions. Two decay scenarios of stopped LLPs are explored: a hadronic decay detected in the calorimeter and a decay into muons detected in the muon system. The calorimeter (muon) search covers a period of sensitivity totaling 721 (744) hours in 38.6 (39.0) fb−1 of data collected by the CMS detector in 2015 and 2016. The results are interpreted in several scenarios that predict LLPs. Production cross section limits are set as a function of the mean proper lifetime and the mass of the LLPs, for lifetimes between 100 ns and 10 days. These are the most stringent limits to date on the mass of hadronically decaying stopped LLPs, and this is the first search at the LHC for stopped LLPs that decay to muons.[Figure not available: see fulltext.].
Bagnaschi E, Sakurai K, Borsato M, et al., 2018, Likelihood analysis of the pMSSM11 in light of LHC 13-TeV data, European Physical Journal C: Particles and Fields, Vol: 78, ISSN: 1434-6044
We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from ∼36 /fb of LHC data at 13 TeV and PICO, XENON1T and PandaX-II searches for dark matter scattering, as well as previous accelerator and astrophysical measurements, presenting fits both with and without the (g−2)μ constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses M1,2,3 , a common mass for the first-and second-generation squarks mq~ and a distinct third-generation squark mass mq~3 , a common mass for the first-and second-generation sleptons mℓ~ and a distinct third-generation slepton mass mτ~ , a common trilinear mixing parameter A, the Higgs mixing parameter μ , the pseudoscalar Higgs mass MA and tanβ . In the fit including (g−2)μ , a Bino-like χ~01 is preferred, whereas a Higgsino-like χ~01 is mildly favoured when the (g−2)μ constraint is dropped. We identify the mechanisms that operate in different regions of the pMSSM11 parameter space to bring the relic density of the lightest neutralino, χ~01 , into the range indicated by cosmological data. In the fit including (g−2)μ , coannihilations with χ~02 and the Wino-like χ~±1 or with nearly-degenerate first- and second-generation sleptons are active, whereas coannihilations with the χ~02 and the Higgsino-like χ~±1 or with first- and second-generation squarks may be important when the (g−2)μ constraint is dropped. In the two cases, we present χ2 functions in two-dimensional mass planes as well as their one-dimensional profile projections and best-fit spectra. Prospects remain for discovering strongly-interacting sparticles at the LHC, in both the scenarios with and without the (g−2)μ constraint, as well as for discovering electroweakly-interacting sparticles
Sirunyan AM, Tumasyan A, Adam W, et al., 2018, Search for pair production of excited top quarks in the lepton + jets final state, Physics Letters B, Vol: 778, Pages: 349-370, ISSN: 0370-2693
A search is performed for the pair production of spin-3/2 excited top quarks, each decaying to a top quark and a gluon. The search uses the data collected with the CMS detector from proton–proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9. Events are selected by requiring an isolated muon or electron, an imbalance in the transverse momentum, and at least six jets of which exactly two must be compatible with originating from the fragmentation of a bottom quark. No significant excess over the standard model predictions is found. A lower limit of 1.2 TeV is set at 95% confidence level on the mass of the spin-3/2 excited top quark in an extension of the Randall–Sundrum model, assuming a 100% branching fraction of its decay into a top quark and a gluon. These are the best limits to date in a search for excited top quarks and the first at 13 TeV.
Costa JC, Bagnaschi E, Sakurai K, et al., 2018, Likelihood analysis of the sub-GUT MSSM in light of LHC 13-TeV data, European Physical Journal C: Particles and Fields, Vol: 78, ISSN: 1434-6044
We describe a likelihood analysis using MasterCode of variants of the MSSM in which the soft supersymmetry-breaking parameters are assumed to have universal values at some scale Min below the supersymmetric grand unification scale MGUT , as can occur in mirage mediation and other models. In addition to Min , such ‘sub-GUT’ models have the 4 parameters of the CMSSM, namely a common gaugino mass m1/2 , a common soft supersymmetry-breaking scalar mass m0 , a common trilinear mixing parameter A and the ratio of MSSM Higgs vevs tanβ , assuming that the Higgs mixing parameter μ>0 . We take into account constraints on strongly- and electroweakly-interacting sparticles from ∼36 /fb of LHC data at 13 TeV and the LUX and 2017 PICO, XENON1T and PandaX-II searches for dark matter scattering, in addition to the previous LHC and dark matter constraints as well as full sets of flavour and electroweak constraints. We find a preference for Min∼105 to 109GeV , with Min∼MGUT disfavoured by Δχ2∼3 due to the BR(Bs,d→μ+μ−) constraint. The lower limits on strongly-interacting sparticles are largely determined by LHC searches, and similar to those in the CMSSM. We find a preference for the LSP to be a Bino or Higgsino with mχ~01∼1TeV , with annihilation via heavy Higgs bosons H / A and stop coannihilation, or chargino coannihilation, bringing the cold dark matter density into the cosmological range. We find that spin-independent dark matter scattering is likely to be within reach of the planned LUX-Zeplin and XENONnT experiments. We probe the impact of the (g−2)μ constraint, finding similar results whether or not it is included.
Aaij R, Adeva B, Adinolfi M, et al., 2017, Measurement of the Y(nS) polarizations in pp collisions at √s = 7 and 8 TeV, The Journal of High Energy Physics, Vol: 2017, ISSN: 1029-8479
The polarization of the Y(1S), Y(2S) and Y(3S) mesons, produced in pp collisions at centre-of-mass energies s√=7 and 8 TeV, is measured using data samples collected by the LHCb experiment, corresponding to integrated luminosities of 1 and 2 fb−1, respectively. The measurements are performed in three polarization frames, using Y → μμ decays in the kinematic region of the transverse momentum p T Υ < 30 GeV/c and rapidity 2.2 < yY < 4.5. No large polarization is observed.Open image in new window
Buchmueller O, De Roeck A, Hahn K, et al., 2017, Simplified models for displaced dark matter signatures, Journal of High Energy Physics, Vol: 2017, ISSN: 1029-8479
We propose a systematic programme to search for long-lived neutral particle signatures through a minimal set of displaced Open image in new window searches (dMETs). Our approach is to extend the well-established dark matter simplified models to include displaced vertices. The dark matter simplified models are used to describe the primary production vertex. A displaced secondary vertex, characterised by the mass of the long-lived particle and its lifetime, is added for the displaced signature. We show how these models can be motivated by, and mapped onto, complete models such as gauge-mediated SUSY breaking and models of neutral naturalness. We also outline how this approach may be used to extend other simplified models to incorporate displaced signatures and to characterise searches for long-lived charged particles. Displaced vertices are a striking signature which is often virtually background free, and thus provide an excellent target for the high-luminosity run of the Large Hadron Collider. The proposed models and searches provide a first step towards a systematic broadening of the displaced dark matter search programme.
Aaij R, Adeva B, Adinolfi M, et al., 2017, Measurement of B-s(0) and D-s(-) Meson Lifetimes, Physical Review Letters, Vol: 119, ISSN: 0031-9007
We report on a measurement of the flavor-specific B0s lifetime and of the D−s lifetime using proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to 3.0 fb−1 of integrated luminosity. Approximately 407 000 B0s→D(*)−sμ+νμ decays are partially reconstructed in the K+K−π−μ+ final state. The B0s and D−s natural widths are determined using, as a reference, kinematically similar B0→D(*)−μ+νμ decays reconstructed in the same final state. The resulting differences between widths of B0s and B0 mesons and of D−s and D− mesons are ΔΓ(B)=−0.0115±0.0053(stat)±0.0041(syst) ps−1 and ΔΓ(D)=1.0131±0.0117(stat)±0.0065(syst) ps−1, respectively. Combined with the known B0and D− lifetimes, these yield the flavor-specific B0s lifetime, τfsB0s=1.547±0.013(stat)±0.010(syst)±0.004(τB) ps and the D−s lifetime, τD−s=0.5064±0.0030(stat)±0.0017(syst)±0.0017(τD) ps. The last uncertainties originate from the limited knowledge of the B0 and D− lifetimes. The results improve upon current determinations.
Aaij R, Adeva B, Adinolfi M, et al., 2017, Measurement of Bs0 and Ds− meson lifetimes, Physical Review Letters, Vol: 119, Pages: 101801-1-101801-10, ISSN: 0031-9007
We report on a measurement of the flavor-specific B0s lifetime and of the D−s lifetime using proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to 3.0 fb−1 of integrated luminosity. Approximately 407 000 B0s→D(*)−sμ+νμ decays are partially reconstructed in the K+K−π−μ+ final state. The B0s and D−s natural widths are determined using, as a reference, kinematically similar B0→D(*)−μ+νμ decays reconstructed in the same final state. The resulting differences between widths of B0s and B0 mesons and of D−s and D− mesons are ΔΓ(B)=−0.0115±0.0053(stat)±0.0041(syst) ps−1 and ΔΓ(D)=1.0131±0.0117(stat)±0.0065(syst) ps−1, respectively. Combined with the known B0 and D− lifetimes, these yield the flavor-specific B0s lifetime, τfsB0s=1.547±0.013(stat)±0.010(syst)±0.004(τB) ps and the D−s lifetime, τD−s=0.5064±0.0030(stat)±0.0017(syst)±0.0017(τD) ps. The last uncertainties originate from the limited knowledge of the B0 and D− lifetimes. The results improve upon current determinations.
Sirunyan AM, Tumasyan A, Adam W, et al., 2017, Search for dijet resonances in proton-proton collisions at root s=13 TeV and constraints on dark matter and other models, Physics Letters B, Vol: 769, Pages: 520-542, ISSN: 0370-2693
A search is presented for narrow resonances decaying to dijet final states in proton–proton collisions at using data corresponding to an integrated luminosity of 12.9 fb−1. The dijet mass spectrum is well described by a smooth parameterization and no significant evidence for the production of new particles is observed. Upper limits at 95% confidence level are reported on the production cross section for narrow resonances with masses above 0.6 TeV. In the context of specific models, the limits exclude string resonances with masses below 7.4 TeV, scalar diquarks below 6.9 TeV, axigluons and colorons below 5.5 TeV, excited quarks below 5.4 TeV, color-octet scalars below 3.0 TeV, bosons below 2.7 TeV, bosons below 2.1 TeV and between 2.3 and 2.6 TeV, and RS gravitons below 1.9 TeV. These extend previous limits in the dijet channel. Vector and axial-vector mediators in a simplified model of interactions between quarks and dark matter are excluded below 2.0 TeV. The first limits in the dijet channel on dark matter mediators are presented as functions of dark matter mass and are compared to the exclusions of dark matter in direct detection experiments.
Bagnaschi E, Borsato M, Sakurai K, et al., 2017, Likelihood analysis of the minimal AMSB model, EUROPEAN PHYSICAL JOURNAL C, Vol: 77, ISSN: 1434-6044
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- Citations: 25
Buchmueller O, Doglioni C, Wang L-T, 2017, Search for dark matter at colliders, NATURE PHYSICS, Vol: 13, Pages: 217-223, ISSN: 1745-2473
Bagnaschi E, Costa JC, Sakurai K, et al., 2017, Likelihood analysis of supersymmetric SU(5) GUTs, EUROPEAN PHYSICAL JOURNAL C, Vol: 77, ISSN: 1434-6044
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- Citations: 21
Khachatryan V, Sirunyan AM, Tumasyan A, et al., 2017, Search for top squark pair production in compressed-mass-spectrum scenarios in proton-proton collisions at √s=8 TeV using the αT variable, PHYSICS LETTERS B, Vol: 767, Pages: 403-430, ISSN: 0370-2693
An inclusive search is performed for supersymmetry in final states containing jets and an apparent imbalance in transverse momentum, View the MathML sourcep→Tmiss, due to the production of unobserved weakly interacting particles in pp collisions at a centre-of-mass energy of 8 TeV. The data, recorded with the CMS detector at the CERN LHC, correspond to an integrated luminosity of 18.5 fb−1. The dimensionless kinematic variable αTαT is used to discriminate between events with genuine View the MathML sourcep→Tmiss associated with unobserved particles and spurious values of View the MathML sourcep→Tmiss arising from jet energy mismeasurements. No excess of event yields above the expected standard model backgrounds is observed. The results are interpreted in terms of constraints on the parameter space of several simplified models of supersymmetry that assume the pair production of top squarks. The search provides sensitivity to a broad range of top squark (View the MathML sourcet˜) decay modes, including the two-body decay View the MathML sourcet˜→cχ˜10, where c is a charm quark and View the MathML sourceχ˜10 is the lightest neutralino, as well as the four-body decay View the MathML sourcet˜→bff¯′χ˜10, where b is a bottom quark and f and View the MathML sourcef¯′ are fermions produced in the decay of an intermediate off-shell W boson. These modes dominate in scenarios in which the top squark and lightest neutralino are nearly degenerate in mass. For these modes, top squarks with masses as large as 260 and 225 GeV are excluded, respectively, for the two- and four-body decays.
Albert A, Bauer M, Brooke J, et al., 2017, Towards the next generation of simplified Dark Matter models, Physics of the Dark Universe, Vol: 16, Pages: 49-70, ISSN: 2212-6864
This White Paper is an input to the ongoing discussion about the extension and refinement of simplified Dark Matter (DM) models. It is not intended as a comprehensive review of the discussed subjects, but instead summarises ideas and concepts arising from a brainstorming workshop that can be useful when defining the next generation of simplified DM models (SDMM). In this spirit, based on two concrete examples, we show how existing 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. 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 review important aspects of supersymmetric models for DM and use them to propose how to develop more complete SDMMs.
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