Charged Higgs Mass Bounds from b -> s gamma in a Bilinear R-Parity Violating Model

Abstract

The experimental measurement of $B(b\to s\gamma )$ imposes important constraints on the charged Higgs boson mass in the MSSM. If squarks are in the few TeV range, the charged Higgs boson mass in the MSSM must satisfy $m_{H^{\pm }}\text{gsim}440$ GeV. For lighter squarks, then light charged Higgs bosons can be reconciled with $B(b\to s\gamma )$ only if there is also a light chargino. In the MSSM if we impose $m_{{\chi }_1^{\pm }}>90$ GeV then we need $m_{H^{\pm }}\text{gsim}110$ GeV. We show that by adding bilinear R--Parity violation (BRpV) in the tau sector, these bounds are relaxed. The bound on $m_{H^{\pm }}$ in the MSSM--BRpV model is $\text{gsim}340$ GeV for the the heavy squark case and $m_{H^{\pm }}\text{gsim}75$ GeV for the case of light squarks. In this case the charged Higgs bosons would be observable at LEP II. The relaxation of the bounds is due mainly to the fact that charged Higgs bosons mix with staus and they contribute importantly to $B(b\to s\gamma )$.

Comments: 20 pages, including 9 figures, LaTeX. new version with some minor mistakes are corrected and the the latest CLEO limits are introduced