The extent of the stop coannihilation strip

Ellis, John; Olive, Keith A.; Zheng, Jiaming

doi:10.1140/epjc/s10052-014-2947-7

Cited by 73 publications

(110 citation statements)

References 113 publications

(82 reference statements)

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“…Alternatively, there might be one or more heavier supersymmetric particles that are nearly degenerate with the LSP, χ, and would have coannihilated with it in the early Universe [37]. There are several examples of possible coannihilating sparticles, including the lighter stau, or possibly some other slepton [38][39][40][41][42][43][44][45], the lighter stop squark [46][47][48][49][50][51][52][53][54][55][56], the lighter chargino [55,[57][58][59][60] and the gluino [56,[61][62][63][64][65][66][67][68][69][70][71][72].…”

Section: Introductionmentioning

confidence: 99%

Scenarios for gluino coannihilation

Ellis

Evans

Luo

et al. 2016

J. High Energ. Phys.

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We study supersymmetric scenarios in which the gluino is the next-to-lightest supersymmetric particle (NLSP), with a mass sufficiently close to that of the lightest supersymmetric particle (LSP) that gluino coannihilation becomes important. One of these scenarios is the MSSM with soft supersymmetry-breaking squark and slepton masses that are universal at an input GUT renormalization scale, but with non-universal gaugino masses. The other scenario is an extension of the MSSM to include vector-like supermultiplets. In both scenarios, we identify the regions of parameter space where gluino coannihilation is important, and discuss their relations to other regions of parameter space where other mechanisms bring the dark matter density into the range allowed by cosmology. In the case of the non-universal MSSM scenario, we find that the allowed range of parameter space is constrained by the requirement of electroweak symmetry breaking, the avoidance of a charged LSP and the measured mass of the Higgs boson, in particular, as well as the appearance of other dark matter (co)annihilation processes. Nevertheless, LSP masses m χ 8 TeV with the correct dark matter density are quite possible. In the case of pure gravity mediation with additional vector-like supermultiplets, changes to the anomalymediated gluino mass and the threshold effects associated with these states can make the gluino almost degenerate with the LSP, and we find a similar upper bound.

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Section: Introductionmentioning

confidence: 99%

Scenarios for gluino coannihilation

Ellis

Evans

Luo

et al. 2016

J. High Energ. Phys.

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“…Their importance to Ωχ0 1 h 2 has been discussed in Refs. [11,18]. Our corrections to the given channels enter the total cross section σ ann in the Boltzmann equation (1.3).…”

Section: Introductionmentioning

confidence: 99%

SUSY-QCD corrections to stop annihilation into electroweak final states including Coulomb enhancement effects

et al. 2015

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We present the full O(αs) supersymmetric QCD corrections for stop-antistop annihilation into electroweak final states within the Minimal Supersymmetric Standard Model. We also incorporate Coulomb corrections due to gluon exchange between the incoming stops. Numerical results for the annihilation cross sections and the predicted neutralino relic density are presented. We show that the impact of the radiative corrections on the cosmologically preferred region of the parameter space can become larger than the current experimental uncertainty, shifting the relic bands within the considered regions of the parameter space by up to a few tens of GeV.PACS numbers: 12.38. Bx,12.60.Jv,95.30.Cq,95.35.+d

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“…They are able to lead to the correct relic density of dark matter through co-annihilation of the neutralino with the light stop [140][141][142][143][144], and they also enable electroweak baryogenesis (EWBG) sufficiently strong to explain the matter-antimatter asymmetry present in the universe today. Electroweak baryogenesis refers to any mechanism that produces an asymmetry in the density of baryons during the electroweak phase transition.…”

Section: Overviewmentioning

confidence: 99%

Beyond Standard Model Collider Phenomenology of Higgs Physics and Supersymmetry

Thomas¹

2016

Springer Theses

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In this thesis I study the collider phenomenology of BSM physics at the LHC, concentrating on the Higgs boson and supersymmetery. The implications and effects on cross sections of the loss of unitarity in scattering processes involving multiple vector bosons and/or the Higgs, when the Higgs couplings to the W and the Z are non-SM, is studied using an effective Lagrangian. Subsequently methods to remove unwanted background from transversely polarised vector bosons are explored, which enable an estimation of the potential to measure the Higgs couplings to weak bosons in a model-independent way via vector boson fusion. MSSM effects on Higgs production and decay are also considered, concentrating on the effects due to light stops, sbottoms and staus. Amongst other things, we find that light 3 rd generation squarks generally produce asymmetrical alteration in signal strengths of different production channels, generally causing µ V BF µ ggF > 1. Finally we extend some ATLAS analyses in the low ∆m = mt − mχ0 1 region, extending the excluded masses of light stops. This enables us to limit the maximum effects of light stops on the Higgs, and further limits the parameter space where the light stop scenario of electroweak baryogenesis is viable.

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The extent of the stop coannihilation strip

Cited by 73 publications

References 113 publications

Scenarios for gluino coannihilation

Scenarios for gluino coannihilation

SUSY-QCD corrections to stop annihilation into electroweak final states including Coulomb enhancement effects

Beyond Standard Model Collider Phenomenology of Higgs Physics and Supersymmetry

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