Resolving the sign ambiguity in Delta Gammas with Bs -> Ds K
Abstract
The analysis of tagged Bs -> J/psi phi decays determines the CP phase phis in Bs-anti-Bs mixing with a two-fold ambiguity. The solutions differ in the sign of cos(phis) which equals the sign of the width difference Delta Gammas among the two Bs mass eigenstates. We point out that this ambiguity can be removed with the help of Bs -> Ds K decays. We compare untagged and tagged strategies and find the tagged analysis more promising. The removal of the sign ambiguity in Delta Gammas can be done with relatively low statistics and could therefore be a target for the early stage of Bs -> Ds K studies.
0