Publications by Ulrich Haisch


New physics in Γ<inf>12</inf><sup>s</sup>: (s̄b) (τ̄τ) operators

Acta Physica Polonica B 44 (2013) 127-176

C Bobeth, U Haisch

Measurements performed at the Tevatron of both the like-sign dimuon charge asymmetry in Bd,s-meson samples and the mixing-induced CP asymmetry in Bs → J/ψφ depart from their Standard Model (SM) predictions. This could be an indication for new CP phases in δB = 2 transitions, preferentially in Bs- B̄s mixing. The experimental situation, however, remained inconclusive, as it favored values of the element Γs12 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 δB = 1 sector as well. The very recent LHCb measurements of Bs → J/ψφ and B s → J/φfo, which do not find any evidence for a new-physics phase in the element Ms12 of the mass matrix, point into this direction as well. In this article, we explore the potential size of non-standard effects in Γ12s stemming from dimension-six operators with flavor content (s̄b)(τ̄τ). We show that since the existing constraints imposed by tree- and loop-level mediated Bd,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- B̄s mixing that can arise from leptoquarks or Z' bosons.


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