Measurement of the CKM angle γ and B0s-B¯¯¯¯0s mixing frequency with B0s→D∓sh±π±π∓ decays

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Abstract

The CKM angle γ is measured for the first time from mixing-induced CP violation between B0s→D∓sK±π±π∓Bs0→Ds∓K±π±π∓ and B¯¯¯¯0s→D±sK∓π∓π±B¯s0→Ds±K∓π∓π± decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 fb1 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-B¯¯¯¯0sBs0-B¯s0 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)∘γ=(44−13+20)∘ modulo 180°. Moreover, the B0s-B¯¯¯¯0sBs0-B¯s0 oscillation frequency is measured from the flavour-specific control channel B0s→D−sπ+π+π−Bs0→Ds−π+π+π− to be ∆ms = (17.757 ± 0.007(stat) ± 0.008(syst)) ps1, consistent with and more precise than the current world-average value.

Original languageEnglish
Article number137
Number of pages46
JournalJournal of High Energy Physics
Volume2021
Issue number3
DOIs
Publication statusPublished - 15-Mar-2021

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