How to extractCP-violating asymmetries from angular correlations

Abstract

Large $\mathrm{CP}$-violation effects can occur for time-evolved $B^0$ decays into definite $\mathrm{CP}$ eigenstates. The rates into these unique $\mathrm{CP}$ eigenmodes are tiny. This article advocates the use of many additional modes that are not $\mathrm{CP}$ eigenstates because of mixtures of angular momenta. Naively, for those modes a partial and sometimes large cancellation of the $\mathrm{CP}$ asymmetry occurs. However, a detailed study of their angular correlations enables the projection onto definite $\mathrm{CP}$ eigenstates, and thus recovers the full $\mathrm{CP}$ asymmetry.