Measurement of CP asymmetry in B_s⁰→ D_s^∓K^± decays

We report on measurements of the time-dependent CP violating observables in Bs 0→ Ds ∓K±decays using a dataset corresponding to 1.0 fb−1of pp collisions recorded with the LHCb detector. We find the CP violating observables Cf= 0.53±0.25±0.04, Af ΔΓ= 0.37 ± 0.42 ± 0.20, (Formula presented.), where the uncertainties are statistical and systematic, respectively. Using these observables together with a recent measurement of the Bs 0mixing phase −2βsleads to the first extraction of the CKM angle γ from Bs 0→ Ds ∓K±decays, finding γ = (115− 43 + 28)° modulo 180° at 68% CL, where the error contains both statistical and systematic uncertainties.