Probing CP violation in semi-leptonic decays through time-evolution

Abstract

We discuss the role of time-dependent observables in probing CP-violation in 𝑏 → 𝑠ℓ + ℓ − and 𝑏 → 𝑠𝜈 ν decays. We identify a set of new observables by looking at the time evolution of the differential decay rate of 𝐵 𝑑 → 𝐾 𝑆 ℓ + ℓ − and 𝐵 𝑑 → 𝐾 𝑆 𝜈 ν where the interference of 𝐵 𝑑 − B𝑑 meson mixing and decay is probed. We show that these observables do not require a timedependent analysis but could be obtained by time-integrated or time-asymmetries if flavour tagging is available. These observables are precisely predicted in the SM, are unaffected by NP in models with real contributions to SM and chirally flipped operators, are independent of form factors, and are unaffected by hadronic uncertainties. They are however sensitive probes of NP scenarios involving new CP-odd phases.