CP violation in charged Higgs boson decays in the MSSM with complex parameters Original Research Article

Supersymmetric loop contributions can lead to different decay rates of H+→tb̄ and H−→bt̄. We calculate the decay rate asymmetry δCP=[Γ(H+→tb̄)−Γ(H−→bt̄)]/[Γ(H+→tb̄)+Γ(H−→bt̄)] at next-to-leading order in the MSSM with complex parameters. We analyse the parameter dependence of δCP with emphasis on the phases of At and Ab. It turns out that the most important contribution comes from the loop with stop, sbottom, and gluino. If this contribution is present, δCP can go up to ∼10–15% for tanβ∼10, and to ∼5% for very large values of tanβ.