In pursuit of new physics with B-s decays - art. no. 114015

The presence of a sizable CP-violating phase in B-s-(B) over bar (s) mixing would be an unambiguous signal of physics beyond the standard model. We an alyze various possibilities to detect such a new phase considering both tag ged and untagged decays. The effects of a sizable width difference Delta Ga mma between the B-s mass eignstates, on which the untagged analyses rely, a re included in all formulas. A novel method to find this phase from simple measurements of lifetimes and branching ratios in untagged decays is propos ed. This method does not involve two-exponential fits, which require much l arger statistics. For the tagged decays, an outstanding role is played by t he observables of the time-dependent angular distribution of the B-s-->J/ps i[-->l(+)l(-)]phi[-->K+K-] decay products. We list the formulas needed for the angular analysis in the presence of both a new CP-violating phase and a sizable Delta Gamma, and propose methods to remove a remaining discrete am biguity in the new phase. This phase can therefore be determined in an unam biguous way.