Measurement of the CKM angle γ and B0s -B0s mixing frequency with B0s → D∓ s h±π±π∓ decays

The CKM angle γ is measured for the first time from mixing-induced CP
violation between B0s → D∓s K±π±π∓ and B0s → D±s K∓π∓π± decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 fb−1 recorded with the LHCb detector. A time-dependent amplitude analysis is performed to extract the CP -violating weak phase γ − 2βs and, subsequently, γ by taking the B0s -B0s mixing phase βs as an external input. The measurement yields γ = (44 ± 12)◦ modulo 180◦, where
statistical and systematic uncertainties are combined. An alternative model-independent measurement, integrating over the five-dimensional phase space of the decay, yields γ =(44 + 20− 13)◦ modulo 180◦. Moreover, the B0s -B0
s oscillation frequency is measured from the flavour-specific control channel B0
s → D−s π+π+π− to be ∆ms = (17.757 ± 0.007(stat) ±0.008(syst)) ps−1, consistent with and more precise than the current world-average value.