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. © 2014 The Author(s).