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

Abstract

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.

Electroweak contributions to squark pair production at the CERN LHC

“…If we keep the sign of the gluino mass parameter positive, the sign of the t − u interference terms, which require a helicity flip, will change. 8 We see that taking M 2 large and negative will lead to cross sections that are sig- 6 The phenomenology of models with large SU (2) gaugino mass parameter has recently been discussed in [23]; however, EW contributions to squark pair production were not considered in that paper. 7 Maximizing the cross section with respect to M 2 and mg would prefer mg slightly below M 2 .…”

Monojet plus soft dilepton signal from light higgsino pair production at LHC14

“…Low values of μ 2 can also be obtained by allowing nonuniversality in the gaugino sector. Models with high values of the GUT scale wino mass parameter [23] or low values of the gluino mass parameter [24] that lead to relatively low values of jμj have been suggested in the context of well-tempered weakly interacting massive particles (WIMPs). In a recent study [25], Martin has suggested a model where the SUSY breaking F-term also breaks the GUT symmetry via a field that is a linear combination of a 1 and 24 dimensional representation of SUð5Þ leading to a nonuniversal pattern of GUT scale gaugino mass parameters [7] that results in a relatively small magnitude of μ.…”

Collider signals and neutralino dark matter detection in relic-density-consistent models without universality

“…Moreover, when a large number of free parameters are varied simultaneously, it is frequently difficult to draw insights into the associated dark matter and collider phenomenology that follow. Instead, many groups [20,21,22,23,24,25,26,27] have examined the impact of relaxing the underlying universality of the mSUGRA model in a controlled way, by allowing non-universal parameters only in one sector of parameter space at a time. For instance, we may consider the mSUGRA parameter space augmented to accommodate non-universal gaugino mass parameters [28] as in (1.3), or instead extended to allow Higgs boson SSB mass parameters to be different from matter scalar mass parameters as in (1.6), but not both.…”