arXiv:0808.3761 Flavor symmetry for strong phases and determination of βs, ∆Γ in Bs → J/ψφ

Studies of angular and time distributions and CP-violating observables in Bs → J/ψφ decays yield a space of parameters which can be considerably reduced if relative strong phases among different amplitudes are specified. We show that the relations between Bs → J/ψφ and B → J/ψK amplitudes given by flavor symmetry [actually U(3) rather than SU(3)] are likely to be quite reliable, and hence the use of strong phases from B → J/ψK in the analysis of Bs → J/ψφ is justified. We point out the potential advantage of using helicity angles over transversity angles, and comment on a way to measure a sizable CP-violating phase independent of strong phases.