The decay b → sγ and the charged Higgs boson mass bounds in a supersymmetric model without R-Parity

The experimental measurement of B(b → sγ)> imposes important constraints on the charged Higgs boson mass in the MSSM. We show that by adding bilinear R-Parity violation (BRpV) in the tau sector, these bounds are relaxed. The bound on mH± in the MSSM-BRpV model is >< 200 - 250 GeV for the the heavy s quark limit. For lighter squarks, light charged Higgs bosons can be reconciled with B(b → sγ) only if there is also a light chargino. In the BRpV model if we impose mκ1± > 90 GeV mH± >< 75 GeV, around 30 GeV down from the MSSM. 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 → sγ)