Light higgsino in heavy gravitino scenario with successful electroweak symmetry breaking

Abstract

We consider, in the context of the minimal supersymmetric standard model, the case where the gravitino weighs 10 6 GeV or more, which is preferred by various cosmological difficulties associated with unstable gravitinos. Despite the large Higgs mixing parameter B together with the little hierarchy to other soft supersymmetry breaking masses, a light higgsino with an electroweak scale mass leads to successful electroweak symmetry breaking, at the price of fine-tuning the higgsino mixing µ parameter. Furthermore the light higgsinos produced at the decays of gravitinos can constitute the dark matter of the universe. The heavy squark mass spectrum of O(10 4 ) GeV can increase the Higgs boson mass to about 125 GeV or higher.

Light higgsino for gauge coupling unification

“…Thus, LSPs are produced below the LSP freeze-out temperature ∼ |µ|/20. If the gravitino abundance is large enough to make annihilation among produced LSPs effective, the LSP relic density becomes independent of the initial gravitino abundance [19,42]:…”

“…shows that EWSB can be achieved when the higgsinos are relatively light and the Higgs sector parameters have the hierarchy [19],…”

“…which is combined with the relations, Eqs. (18) and (19), to put an upper bound on the ratio between m susy and µ:…”

The B−L Phase Transition

“…31 On the other hand, a gravitino heavier than about 10 TeV can be consistent with primordial nucleosynthesis and leptogenesis [126,131,134,135]. In such a scenario, the gravitino then represents the heaviest superparticle-a possibility, which is in fact realized in models of anomaly-mediated supersymmetry breaking [136,137] and which has recently been reconsidered in the case of wino [138], higgsino [139] and bino [140] LSP, because it nicely fits together with a Higgs boson mass of about 125 GeV. In Chap.…”

Untitled

“…Recent results on the Higgs boson mass from the LHC motivate a superparticle mass spectrum with a very heavy gravitino [71,72] m LSP m squark,slepton m G . (6.21) Due to this hierarchy, the LSP is typically a 'pure' gaugino or higgsino.…”