NEW PHYSICS IN Γ12s : ((s)over-barb)((τ)over-barτ) OPERATORS

Measurements performed at the Tevatron of both the like-sign dimuon charge asymmetry in B-d,B-s-meson samples and the mixing-induced CP asymmetry in B-s -> J/psi phi depart from their Standard Model (SM) predictions. This could be an indication for new CP phases in Delta B = 2 transitions, preferentially in B-s-(B) over bar (s) mixing. The experimental situation, however, remained inconclusive, as it favored values of the element Gamma(s)(12) of the decay matrix in the B-s-meson system that are notably different from the SM expectation, suggesting the presence of new physics in the Delta B = 1 sector as well. The very recent LHCb measurements of B-s -> J/psi phi and B-s -> J/psi f(0), which do not find any evidence for a new-physics phase in the element M-12(s) of the mass matrix, point into this direction as well. In this article, we explore the potential size of non-standard effects in Gamma(s)(12) stemming from dimension-six operators with flavor content ((s) over barb) ((tau) over bar tau). We show that since the existing constraints imposed by tree- and loop-level mediated B-d,B-s-meson decays are quite loose, the presence of absorptive new physics of this type would lead to an improved global fit to the current data. The allowed effects are, however, far too small to provide a full explanation of the observed anomalies. Our model-independent conclusions are finally contrasted with explicit analyses of the new-physics effects in B-s-(B) over bar (s) mixing that can arise from leptoquarks or Z' bosons. DOI:10.5506/APhysPolB.44.127