CP violation and the CKM angle γ from angular distributions of untagged Bs decays governed by b → cus

We demonstrate that time-dependent studies of angular distributions for Bs decays caused by b → cus quark-level transitions extract clearly and model-independently the CKM angle γ. This CKM angle could be cleanly determined from untagged Bs decays alone, if the lifetime difference between the Bs mass eigenstates BsL and BsH is sizable. The time dependences for the relevant tagged and untagged observables are given both in a general notation and in terms of linear polarization states and should exhibit large CP-violating effects. These observables may furthermore provide insights into the hadronization dynamics of the corresponding exclusive Bs decays, thereby allowing tests of the factorization hypothesis.