Measurement of the flavour-specific CP-violating asymmetry assl in B0s decays

Abstract

The CP-violating asymmetry as sl is studied using semileptonic decays of B0s and B0s mesons produced in pp collisions at a centre-of-mass energy of 7 TeV at the LHC, exploiting a data sample corresponding to an integrated luminosity of 1.0 fb−1. The reconstructed final states are D± s μ∓, with the D± s particle decaying in the φπ± mode. The D± s μ∓ yields are summed over B0s and B0s initial states, and integrated with respect to decay time. Data-driven methods are used to measure efficiency ratios. We obtain as sl = (−0.06±0.50±0.36)%, where the first uncertainty is statistical and the second systematic.