Gaugino coannihilations

Abstract

The high-scale supersymmetry (SUSY) breaking scenario is now attracting many attentions, because it is consistent with almost all experiments of particle physics, astrophysics, and cosmology performed so far: e.g. it is possible to explain the Higgs mass of about 126 GeV and contains WIMP dark matter candidates. In the scenario, gauginos are predicted to be around the TeV scale, and thus within a kinematically accessible range of near future experiments. Calculation of the thermal relic abundance for gaugino (bino or wino) dark matter is then of particular importance in order to clarify its mass consistent with cosmology and to determine future directions for exploring the high-scale SUSY breaking scenario. In this article, we calculate the abundance of the gaugino dark matter, with especially focusing on various coannihilations between gauginos, which has not been extensively studied so far. Our calculation involves the Sommerfeld effect on wino and gluino annihilations, which is known to give significant contributions to their cross sections. Based on obtained results, we discuss some implications to gaugino searches at collider and indirect detection experiments of dark matter.

Scenarios for gluino coannihilation

“…Another possible way of realizing a spectrum that can lead to gluino coannihilation is in models with pure gravity mediation [124][125][126][127][128][129][130][131] of supersymmetry breaking with additional vector multiplets that are charged under the SM gauge symmetries [67][68][69]. Since the mass spectrum of the gaugino sector of PGM is quite constrained, one of the few viable ways to alter this spectrum is through the addition of vector-like matter with all of its mass coming from a Giudice-Masiero (GM) term [132][133][134] in the Kähler potential.…”

“…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].…”

“…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].…”

Extending the reach of compressed gluinos at the LHC

“…As a case study, we will pick a simplified model with a gluino taken slightly heavier than a bino LSP. We make this choice motivated by its well-known viability in setting the relic abundance of DM by means of co-annihilation [12][13][14][15][16][17][18] and the relative safety of bino DM from limits set by direct detection experiments. The central idea of gluinobino co-annihilation is that while binos self-annihilate inefficiently, naively prompting overclosure of the universe, the simultaneous annihilation of gluinos in the thermal bath can effectively help drive the relic abundance down to the observed value.…”

“…In our analysis, we will not concern ourselves with the precise determination of ∆M required for the observed Ω χ h 2 , since our focus is on the collider search. For gluinos lighter than 8 TeV, it has been computed that ∆M ranges between a few 10's of GeV and 140 GeV [14][15][16][17]. Motivated by this, we set ∆M = 100 GeV (1) throughout the analysis.…”