Dark matter versus h → γγ and h → γZ with supersymmetric triplets

Abstract

The Triplet extension of the MSSM (TMSSM) alleviates the little hierarchy problem and provides a significant enhancement of the loop-induced diphoton rate of the lightest CP-even Higgs h. In this paper we pursue the analysis of the TMSSM Higgs phenomenology by computing for the first time the h → Zγ decay. Interestingly we find that the rates of loop-induced decays are correlated and their signal strengths can rise up to 40%-60% depending on the channel. We furthermore study the dark matter phenomenology of the TMSSM. The lightest neutralino is a good dark matter candidate in two regions. The first one is related to the Higgs and Z resonances and the LSP is mostly Bino. The second one is achieved for a mass larger than 90 GeV and the LSP behaves as the well-tempered neutralino. An advantage of the triplet contribution is that the well-tempered neutralino can be a Bino-Triplino mixture, relieving the problem of achieving M 2 ∼ M 1 in unified scenarios. The dark matter constraints strongly affect the Higgs phenomenology, reducing the potential enhancements of the diphoton and of the Zγ channels by 20% at most. In the near future, dark matter direct searches and collider experiments will probe most of the parameter space where the neutralino is the dark matter candidate.

Naturality vs perturbativity, B s physics, and LHC data in triplet extension of MSSM

“…An important result of the fit is that, for viable data points in the TESSM parameter space, we observe not only an enhancement of the Higgs decay to diphoton, as previously observed in [31,49,50,57], but also a suppression of the same decay rate. This is due to the fact that we scan also negative values of mass and coupling parameters, for which the light chargino mass and its coupling to the light Higgs can have the same sign.…”

“…As figure 4 (right panel) shows, a small mass for the lightest chargino produces a sizable contribution to the decay rate to two photons, as expected, but this contribution can be either constructive or destructive with the one from the W boson: the latter result seems to be in disagreement with results appeared in previous works on the same triplet extension of MSSM that we study here [31,49,50,57].…”

“…The experimental bounds [61] on the mass of pseudoscalars and neutralinos are actually less tight than the ones above, but we prefer to avoid in this general study the phenomenological complicacies of invisible decays of the light Higgs, which are though relevant for dark matter [57]. In section 4 we impose additional, coupling dependent constraints on the heavy neutral Higgses.…”

Multi-lepton signatures of the triplet like charged Higgs at the LHC

“…Recently, it has been shown [33] that the fine-tuning can be reduced significantly when the TESSM is considered, since the extended Higgs sector can generate additional tree level contributions to the light Higgs mass so that sizable quantum corrections are no longer needed [31][32][33]. For the experimentally viable parameter regions of the model it is also possible to obtain an enhancement or a suppression in the Higgs decay to diphoton rate [33][34][35][36].…”

“…Such decays are relevant for the dark matter studies [36]. In the parameter scan, we restrict the trilinear couplings and the squark soft masses less or equal to 2 TeV since in the TESSM a 125 GeV Higgs can be achieved without requiring large mixing between two physical stops and/or large stop masses that are essential in the case of the MSSM [27].…”