Invisible Decays of the Supersymmetric Higgs and Dark Matter

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 $\frac{B.R.(h\to \gamma \gamma {)}_{SUSY}}{B.R.(h\to \gamma \gamma {)}_{SM}}$ 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 $m_0$.

17 pages, 11 figures, Talk presented at Appi2002, Accelerator and Particle Physics Institute, Appi, Iwate, Japan, February 13--16 2002