Invisible Decays of the Supersymmetric Higgs and Dark Matter

TL;DR

This paper explores how light supersymmetric particles can cause the Higgs boson to decay invisibly into neutralinos, affecting its detection prospects at colliders and constraining supersymmetric parameter space.

Contribution

It analyzes the impact of light sparticles on Higgs decays and identifies parameter regions where Higgs detection via gamma gamma channel is hindered, providing new insights into supersymmetric phenomenology.

Findings

Invisible Higgs decays into neutralinos can suppress gamma gamma signals.

Certain parameter regions allow acceptable relic density with reduced gamma gamma branching ratio.

Lower limits on U(1) gaugino mass M_1 are established independently of other parameters.

Abstract

We discuss effects of the light sparticles on decays of the lightest Higgs in a supersymmetric model with nonuniversal gaugino masses at the high scale, focusing on the `invisible' decays into neutralinos. These can impact significanlty the discovery possibilities of the lightest Higgs at the LHC. We show that due to these decays, there exist regions of the $M_2-\mu$ space where the B.R. $(h \to \gamma \gamma)$ becomes dangerously low even after imposing the LEP constraints on the sparticle masses, implying a possible preclusion of its discovery in the $\gamma \gamma$ channel. We find that there exist regions in the parameter space with acceptable relic density and where the ratio ${B.R. (h \to \gamma \gamma)_{SUSY} \over B.R. (h \to \gamma \gamma)_{SM}}$ falls below 0.6, implying loss of signal in the $\gamma \gamma$ channel. These regions correspond to $\tilde \chi_1^+, \tilde \chi_2^0$ masses which should be accessible already at the Tevatron. Further we find that considerations of relic density put lower limit on the U(1) gaugino mass parameter $M_1$ independently of $\mu, \tan \beta$ and $m_0$.