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arXiv · 1605.09768

Measurement of the $CP$ asymmetry in $B_s^0-\overline{B}{}_s^0$ mixing

LHCb collaboration·R. Aaij·B. Adeva·M. Adinolfi·Z. Ajaltouni·S. Akar·J. Albrecht·F. Alessio·M. Alexander·S. Ali·G. Alkhazov·P. Alvarez Cartelle·A. A. Alves Jr·S. Amato·S. Amerio·Y. Amhis·L. An·L. Anderlini·G. Andreassi·M. Andreotti·J. E. Andrews·R. B. Appleby·O. Aquines Gutierrez·F. Archilli·P. d'Argent·J. Arnau Romeu·A. Artamonov·M. Artuso·E. Aslanides·G. Auriemma·M. Baalouch·S. Bachmann·J. J. Back·A. Badalov·C. Baesso·W. Baldini·R. J. Barlow·C. Barschel·S. Barsuk·W. Barter·V. Batozskaya·V. Battista·A. Bay·L. Beaucourt·J. Beddow·F. Bedeschi·I. Bediaga·L. J. Bel·V. Bellee·N. Belloli·K. Belous·I. Belyaev·E. Ben-Haim·G. Bencivenni·S. Benson·J. Benton·A. Berezhnoy·R. Bernet·A. Bertolin·M. -O. Bettler·M. van Beuzekom·S. Bifani·P. Billoir·T. Bird·A. Birnkraut·A. Bitadze·A. Bizzeti·T. Blake·F. Blanc·J. Blouw·S. Blusk·V. Bocci·T. Boettcher·A. Bondar·N. Bondar·W. Bonivento·S. Borghi·M. Borisyak·M. Borsato·F. Bossu·M. Boubdir·T. J. V. Bowcock·E. Bowen·C. Bozzi·S. Braun·M. Britsch·T. Britton·J. Brodzicka·E. Buchanan·C. Burr·A. Bursche·J. Buytaert·S. Cadeddu·R. Calabrese·M. Calvi·M. Calvo Gomez·P. Campana·D. Campora Perez·L. Capriotti·A. Carbone
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Abstract

The $CP$ asymmetry in the mixing of $B_s^0$ and $\overline{B}{}_s^0$ mesons is measured in proton-proton collision data corresponding to an integrated luminosity of 3.0 fb$^{-1}$, recorded by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Semileptonic $B_s^0$ and $\overline{B}{}_s^0$ decays are studied in the inclusive mode $D_s^{\mp} μ^{\pm} ν_μ X$ with the $D_s^{\mp}$ mesons reconstructed in the $K^+ K^- π^{\mp}$ final state. Correcting the observed charge asymmetry for detection and background effects, the $CP$ asymmetry is found to be $a_{\text{sl}}^s = (0.39 \pm 0.26 \pm 0.20) \% $, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of $a_{\text{sl}}^s$ to date. It is consistent with the prediction from the Standard Model and will constrain new models of particle physics.

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LHCb collaboration, R. Aaij, B. Adeva, M. Adinolfi, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves Jr, S. Amato, S. Amerio, Y. Amhis, L. An, L. Anderlini, G. Andreassi, M. Andreotti, J. E. Andrews, R. B. Appleby, O. Aquines Gutierrez, F. Archilli, P. d'Argent, J. Arnau Romeu, A. Artamonov, M. Artuso, E. Aslanides, G. Auriemma, M. Baalouch, S. Bachmann, J. J. Back, A. Badalov, C. Baesso, W. Baldini, R. J. Barlow, C. Barschel, S. Barsuk, W. Barter, V. Batozskaya, V. Battista, A. Bay, L. Beaucourt, J. Beddow, F. Bedeschi, I. Bediaga, L. J. Bel, V. Bellee, N. Belloli, K. Belous, I. Belyaev, E. Ben-Haim, G. Bencivenni, S. Benson, J. Benton, A. Berezhnoy, R. Bernet, A. Bertolin, M. -O. Bettler, M. van Beuzekom, S. Bifani, P. Billoir, T. Bird, A. Birnkraut, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J. Blouw, S. Blusk, V. Bocci, T. Boettcher, A. Bondar, N. Bondar, W. Bonivento, S. Borghi, M. Borisyak, M. Borsato, F. Bossu, M. Boubdir, T. J. V. Bowcock, E. Bowen, C. Bozzi, S. Braun, M. Britsch, T. Britton, J. Brodzicka, E. Buchanan, C. Burr, A. Bursche, J. Buytaert, S. Cadeddu, R. Calabrese, M. Calvi, M. Calvo Gomez, P. Campana, D. Campora Perez, L. Capriotti, A. Carbone. 2016-08-08. Measurement of the $CP$ asymmetry in $B_s^0-\overline{B}{}_s^0$ mixing. https://doi.org/10.1103/physrevlett.117.061803

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