Measurement of CP asymmetry in Bs0 → Ds∓K± decays

Author(s): Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Alfonso Albero, A; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, AA; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, JE; Appleby, RB; Archilli, F; d’Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Atzeni, M; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, JJ; Badalov, A; Baesso, C; Baker, S; Balagura, V; Baldini, W; Baranov, A; Barlow, RJ; Barschel, C; Barsuk, S; Barter, W; Baryshnikov, F; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Beiter, A; Bel, LJ; Beliy, N; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Beranek, S; Berezhnoy, A; Bernet, R; Berninghoff, D; Bertholet, E; Bertolin, A; Betancourt, C; Betti, F; Bettler, MO; van Beuzekom, M; Bezshyiko, I; Bifani, S; Billoir, P; Birnkraut, A; Bizzeti, A; Bjorn, M; Blake, T; Blanc, F; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N | Abstract: © 2018, The Author(s). We report the measurements of the CP -violating parameters in Bs0 → Ds∓K± decays observed in pp collisions, using a data set corresponding to an integrated luminosity of 3.0 fb−1 recorded with the LHCb detector. We measure Cf = 0.73 ± 0.14 ± 0.05, AfΔΓ = 0.39 ± 0.28 ± 0.15, Af=0.31±0.28±0.15, Sf = −0.52 ± 0.20 ± 0.07, Sf¯= − 0.49 ± 0.20 ± 0.07 , where the uncertainties are statistical and systematic, respectively. These parameters are used together with the world-average value of the Bs0 mixing phase, −2βs, to obtain a measurement of the CKM angle γ from Bs0 → Ds∓K± decays, yielding γ = (128− 22+ 17)° modulo 180°, where the uncertainty contains both statistical and systematic contributions. This corresponds to 3.8 σ evidence for CP violation in the interference between decay and decay after mixing.