THE DECAY $H^0_2\to gg$\ WITHIN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL

Abstract

I present a detailed SUSY QCD calculation of the decay rate of the lightest Higgs boson $H^0_2$\ into two gluons, where all quarks and scalar quarks are taken within the relevant loop diagrams. I include the mixing of all the scalar partners of the left and right handed quarks and show that their contribution is more than several tens of per cent compared to the quark contribution in the MSSM for some SUSY parameter space. Furthermore the fermionic contribution is enhanced by several factors for large $\tan\beta$\ and large Higgs masses. As a result, the two gluon decay rate of $H_2^0$\ is much larger than the two gluon decay rate of an equal mass standard model Higgs boson. I further compare the decay mode of $H^0_2\rightarrow gg$\ to the similar decay modes of $H^0_2\rightarrow c\overline c$\ and $H^0_2\rightarrow b\overline b$\ including one loop QCD corrections and show that in some cases $\Gamma(H^0_2\rightarrow gg)$\ is even higher than $\Gamma(H^0_2\rightarrow c\overline c)$, although still much smaller than $\Gamma(H^0_2\rightarrow b\overline b)$.