We analyze nonleptonic Bs​ decays to a charmonium state and a light meson,
induced by the b→ccˉs transition, which are useful to access the
Bs​-Bˉs​ mixing phase βs​. We use generalized factorization and
SU(3)F​ symmetry to relate such modes to correspondent B decay channels. We
discuss the feasibility of the measurements in the various channels, stressing
the importance of comparing different determinations of βs​ in view of
the hints of new physics effects (NP) recently emerged in the Bs​ sector.
Finally, adopting a general parametrization of NP contributions to the decay
amplitudes, we discuss how to experimentally constrain new physics parameters.Comment: LaTeX, 17 pages, 2 Eps figure