New physics effects on the [Formula Presented] asymmetries in [Formula Presented] and [Formula Presented] decays

Abstract

Within the standard model (SM), the time-dependent [Formula Presented] asymmetries in [Formula Presented] [Formula Presented] and [Formula Presented] are expected to give the same result, i.e., [Formula Presented] However, recent measurements of the mixing-induced [Formula Presented] asymmetries in [Formula Presented] and [Formula Presented] modes give results whose central values differ from the SM expectations. We explore the effect of new physics in the two Higgs doublet model (THDM), which allows tree level flavor changing neutral currents (so-called model III), and the model with an extra vectorlike down quark (VLDQ). We find that the observed mixing-induced [Formula Presented] asymmetry for [Formula Presented] cannot be accommodated by the THDM but can be explained in the VLDQ model, and both models can explain the observed asymmetry for [Formula Presented] mode. © 2003 The American Physical Society.