by Michal Kreps
(The University of Warwick)
The Bs mixing phase beta_s is a key probe of physics beyond the standard model (SM). The first Tevatron measurements hinted at a ~2sigma departure from the SM expectations. We present a new analysis using Bs -> J/Psi phi decays reconstructed in 5.2fb-1 of data collected by CDF detector, where tightened bounds on the mixing phase are obtained along with an improved measurement of the decay-width difference.