Enlarging Regions of the MSSM Parameter Space for Large $\tan\beta$ via SUSY Decays of the Heavy Higgs Bosons

Abstract

In the Minimal Supersymmetric Standard Model (MSSM) searches for the heaviest CP-even and CP-odd Higgs $H$, $A$ to tau-lepton pairs severely constrain the parameter region for large values of $\tan\beta$ and light Higgs bosons $H$, $A$. We demonstrate how the experimental constraint can be avoided by new decays to light third-generation sfermions, whose left-right couplings to $H$ can be maximised in regions of large trilinear couplings $A_{b}$, $A_{\tau}$ for sbottoms and staus, or large supersymmetric (SUSY) Higgs mass $\mu$ for stops. Due to the $\tan\beta$-enhancement in the production cross-sections via gluon-fusion and in association with bottom-quark pairs for $H$ and $A$, we find that down-type sfermions, in particular, sbottoms perform a better job in allowing more parameter space than up-type sfermions such as stops, which require much larger values of $\mu$ to compensate for $\tan\beta$. Vacuum stability as well as flavour observables constraints and direct searches for SUSY particles are imposed. We also associate the lightest CP-even Higgs with the observed 125 GeV SM-like Higgs and impose the experimental constraints from the LHC.