Updated Constraints on the Minimal Supergravity Model

Baer, Howard; Balázs, Csaba; Belyaev, A.; Mizukoshi, J. K.; Tata, Xerxes; Wang, Yili

doi:10.1088/1126-6708/2002/07/050

Cited by 129 publications

(81 citation statements)

References 84 publications

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“…There is no strong argument why these parameters should be universal for supersymmetric particles with different quantum numbers, e.g., d, u and e, though this may occur in some grand unified theories, as may unification of the gaugino masses M a . The simplified version of the MSSM in which universality at the grand unification scale is assumed for each of M a , m 2 and A is called the constrained MSSM (CMSSM) [55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78].…”

Section: Renormalization-group Equations and Electroweak Symmetry Brementioning

confidence: 99%

Supersymmetric dark matter candidates

Ellis

Olive²

2010

Particle Dark Matter

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CERN-PH-TH/2010-004, UMN-TH-2831/10, FTPI-MINN-10/02After reviewing the theoretical, phenomenological and experimental motivations for supersymmetric extensions of the Standard Model, we recall that supersymmetric relics from the Big Bang are expected in models that conserve R parity. We then discuss possible supersymmetric dark matter candidates, focusing on the lightest neutralino and the gravitino. In the latter case, the next-to-lightest supersymmetric particle is expected to be long-lived, and possible candidates include spartners of the tau lepton, top quark and neutrino. We then discuss the roles of the renormalization-group equations and electroweak symmetry breaking in delimiting the supersymmetric parameter space. We discuss in particular the constrained minimal extension of the Standard Model (CMSSM), in which the supersymmetry-breaking parameters are assumed to be universal at the grand unification scale, presenting predictions from a frequentist analysis of its parameter space. We also discuss astrophysical and cosmological constraints on gravitino dark matter models, as well as the parameter space of minimal supergravity (mSUGRA) models in which there are extra relations between the trilinear and bilinear supersymmetry-breaking parameters, and between the gravitino and scalar masses. Finally, we discuss models with non-universal supersymmetry-breaking contributions to Higgs masses, and models in which the supersymmetry-breaking parameters are universal at some scale below that of grand unification. From 'Particle Dark Matter: Observations, Models and Searches' edited byGianfranco Bertone

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Section: Renormalization-group Equations and Electroweak Symmetry Brementioning

confidence: 99%

Supersymmetric dark matter candidates

Ellis

Olive²

2010

Particle Dark Matter

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“…The branching fraction BF (b → sγ) is extremely interesting largely because amplitudes for supersymmetric contributions mediated by W itj and bH + loops are expected to be of similar size as the leading SM amplitude mediated by a tW loop [37]. The measured branching fraction, from a combination of CLEO, Belle and BABAR experiments [32], is BF (b → sγ) = (3.55 ± 0.26) × 10 −4 , while the latest SM calculations find [38] BF (b → sγ) = (3.29± 0.33)× 10 −4 .…”

Section: Bf (B → Sγ)mentioning

confidence: 99%

“…We evaluate BF (b → sγ) using the IsaBSG code [37], a part of the Isatools package. The dependence of the branching fraction on r 2 is illustrated in figure 9 for our canonical point 1 from table 1.…”

Section: Bf (B → Sγ)mentioning

confidence: 99%

Mixed higgsino dark matter from a large SU(2) gaugino mass

Baer

Mustafayev

Summy

et al. 2007

J. High Energy Phys.

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We observe that in SUSY models with non-universal GUT scale gaugino mass parameters, raising the GUT scale SU(2) gaugino mass |M 2 | from its unified value results in a smaller value of −m 2Hu at the weak scale. By the electroweak symmetry breaking conditions, this implies a reduced value of µ 2 visà vis models with gaugino mass unification. The lightest neutralino can then be mixed Higgsino dark matter with a relic density in agreement with the measured abundance of cold dark matter (DM). We explore the phenomenology of this high |M 2 | DM model. The spectrum is characterized by a very large wino mass and a concomitantly large splitting between left-and right-sfermion masses. In addition, the lighter chargino and three light neutralinos are relatively light with substantial higgsino components. The higgsino content of the LSP implies large rates for direct detection of neutralino dark matter, and enhanced rates for its indirect detection relative to mSUGRA. We find that experiments at the LHC should be able to discover SUSY over the portion of parameter space where mg < ∼ 2350 − 2750 GeV, depending on the squark mass, while a 1 TeV electron-positron collider has a reach comparable to that of the LHC. The dilepton mass spectrum in multi-jet + ℓ + ℓ − + E miss T events at the LHC will likely show more than one mass edge, while its shape should provide indirect evidence for the large higgsino content of the decaying neutralinos.

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“…The possibility of gluino coannihilation does not arise in the minimal supersymmetric extension of the Standard Model (MSSM) with the soft supersymmetry-breaking parameters constrained to be universal at the input GUT scale (the CMSSM) [14,[32][33][34][35][36][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92], nor in related models with non-universal Higgs masses [83,84,[93][94][95][96][97][98][99][100][101][102][103][104][105][106]. However, as we discuss in this paper, gluino coannihilation can become important in variants of the MSSM with non-universal gaugino masses, and in variations of pure gravity mediation (PGM) with non-minimal matter content such as additional vector-like supermultiplets [67][68][69].…”

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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Updated Constraints on the Minimal Supergravity Model

Cited by 129 publications

References 84 publications

Supersymmetric dark matter candidates

Supersymmetric dark matter candidates

Mixed higgsino dark matter from a large SU(2) gaugino mass

Scenarios for gluino coannihilation

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