C P asymmetries of B → Xs/Xdγ in models with three Higgs doublets

Direct CP asymmetries (ACP) in the inclusive decays of B → Xsγ and B → Xs+dγ of the order of 1% will be probed at the BELLE II experiment. In this work, three such asymmetries are studied in the context of a three-Higgs-doublet model (3HDM), and it is shown that all three ACP can be as large as the current experimental limits. Of particular interest is the ACP for B → Xs+dγ, which is predicted to be effectively zero in the Standard Model (SM). A measurement of 2.5% or more for this observable with the full BELLE II data would give 5σ evidence for physics beyond the SM. We display parameter space in the 3HDM for which such a clear signal is possible.