CP violation and CKM phases from angular distributions for $B_s$ decays into admixtures of CP eigenstates

Abstract

We investigate the time-evolutions of angular distributions for $B_s$ decays into final states that are admixtures of CP-even and CP-odd configurations. A sizable lifetime difference between the $B_s$ mass eigenstates allows a probe of CP violation in time-dependent untagged angular distributions. Interference effects between different final state configurations of $B_s\to D^{*+}_s D^{*-}_s$, $J/ψϕ$ determine the Wolfenstein parameter $η$ from untagged data samples, or -- if one uses $|V_{ub}|/|V_{cb}|$ as an additional input -- the notoriously difficult to measure CKM angle $γ$. Another determination of $γ$ is possible by using isospin symmetry of strong interactions to relate untagged data samples of $B_s\to K^{\ast+} K^{\ast-}$ and $B_s\to K^{\ast0} \overline{K^{\ast0}}$. We note that the untagged angular distribution for $B_s\toρ^0 ϕ$ provides interesting information about electroweak penguins.