Testing the Standard Model with CP asymmetries in flavor-specific nonleptonic decays

Abstract

Motivated by recent indications that the rates of color-allowed nonleptonic channels are not in agreement with their Standard Model expectations based on QCD factorization, we investigate the potential to study $CP$ asymmetries with these decays. In the Standard Model, these flavor-specific decays are sensitive to $CP$ violation in ${B}_{(s)}^{0}--{\overline{B}}_{(s)}^{0}$ mixing, which is predicted with low uncertainties and can be measured precisely with semileptonic decays. Allowing beyond Standard Model (BSM) contributions to the nonleptonic decay amplitudes, we derive explicit expressions for the flavor-specific $CP$ asymmetries in a model-independent way. We find that BSM contributions could lead to significant enhancements to the $CP$ asymmetries. Therefore measurements of these quantities and subsequent comparison with the $CP$ asymmetries measured with semileptonic decays have potential to identify BSM effects without relying on Standard Model predictions that might be affected by hadronic effects. In addition, we discuss the experimental prospects, and note the excellent potential for a precise determination of the $CP$ asymmetry in ${\overline{B}}_{s}\ensuremath{\rightarrow}{D}_{s}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays by the LHCb experiment.