Time dependence in B → V ℓℓ decays

Abstract

Abstract: We discuss the theory and phenomenology of Bd,s → V (→ M1M2)ℓℓ decays in the presence of neutral-meson mixing. We derive expressions for the time-dependent angular distributions for decays into CP eigenstates, and identify the relevant observables that can be extracted from time-integrated and time-dependent analyses with or without tagging, with a focus on the difference between measurements at B-factories and hadronic machines. We construct two observables of interest, which we call Q8− and Q9, and which are theoretically clean at large recoil. We compute these two observables in the Standard Model, and show that they have good potential for New Physics searches by considering their sensitivity to benchmark New Physics scenarios consistent with current b → sℓℓ data. These results apply to decays such as Bd → K∗(→ KS π0)ℓℓ, Bs → ϕ(→ KSKL)ℓℓ and Bs → ϕ(→ K+K−)ℓℓ.