The mass of the charged Higgs boson in the minimal supersymmetric standardmodel with explicit CP violation at 1-loop level

The mass of the charged Higgs boson at the I-loop level is investigated, as suming the CP symmetry to be violated explicitly in the Higgs sector of the minimal supersymmetric standard model (MSSM). It is found that there is a parameter region of the MSSM where the presence of explicit CP violation in the Higgs sector yields negative radiative corrections to the charged Higg s boson mass. Thus, the charged Higgs boson in the MSSM may have as low a m ass as 60 GeV at the 1-loop level, if the CP symmetry is violated. This low er bound may be improved by the Higgs search at LEP2, which imposes experim ental constraints on the charged Higgs mass, as well as on the masses of th e neutral Higgs bosons. Hence, LEP2 can constrain experimentally the charge d Higgs mass to be not smaller than 109 GeV under our assumption. In additi on, it sets 75 GeV as the lower bound on the mass of the lightest neutral H iggs boson, and 84 GeV for that of the next-to-lightest neutral Higgs boson .