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arXiv · 2603.10860

First measurement of the decay-time-integrated $C\!P$ asymmetry in $B_s^0 \to D_s^- \pi^+$ decays

LHCb collaboration·R. Aaij·M. Abdelfatah·A. S. W. Abdelmotteleb·C. Abellan Beteta·F. Abudinén·T. Ackernley·A. A. Adefisoye·B. Adeva·M. Adinolfi·P. Adlarson·C. Agapopoulou·C. A. Aidala·Z. Ajaltouni·S. Akar·K. Akiba·P. Albicocco·J. Albrecht·R. Aleksiejunas·F. Alessio·P. Alvarez Cartelle·R. Amalric·S. Amato·J. L. Amey·Y. Amhis·L. An·L. Anderlini·M. Andersson·P. Andreola·M. Andreotti·S. Andres Estrada·A. Anelli·D. Ao·C. Arata·F. Archilli·Z. Areg·M. Argenton·S. Arguedas Cuendis·L. Arnone·M. Artuso·E. Aslanides·R. Ataíde Da Silva·M. Atzeni·B. Audurier·J. A. Authier·D. Bacher·I. Bachiller Perea·S. Bachmann·M. Bachmayer·J. J. Back·Z. B. Bai·P. Baladron Rodriguez·V. Balagura·A. Balboni·W. Baldini·Z. Baldwin·L. Balzani·H. Bao·J. Baptista de Souza Leite·C. Barbero Pretel·M. Barbetti·I. R. Barbosa·R. J. Barlow·M. Barnyakov·S. Barsuk·W. Barter·J. Bartz·S. Bashir·B. Batsukh·P. B. Battista·A. Bavarchee·A. Bay·A. Beck·M. Becker·F. Bedeschi·I. B. Bediaga·N. A. Behling·S. Belin·A. Bellavista·I. Belov·I. Belyaev·G. Benane·G. Bencivenni·E. Ben-Haim·R. Bernet·A. Bertolin·F. Betti·J. Bex·O. Bezshyyko·S. Bhattacharya·M. S. Bieker·N. V. Biesuz·A. Biolchini·M. Birch·F. C. R. Bishop·A. Bitadze·A. Bizzeti·T. Blake·F. Blanc·J. E. Blank
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Abstract

A measurement of the flavor-untagged decay-time-integrated ${C\!P}$ asymmetry in the flavor-specific decay ${B_s^0 \to D_s^-\pi^+}$, ${\langle A^s_{\rm untagged}\rangle}$, is performed using proton-proton collision data collected by the LHCb experiment between 2016 and 2018 at a center-of-mass energy of ${13\,{\rm TeV}}$, corresponding to a total integrated luminosity of ${5.4\,{\rm fb}^{-1}}$. The ${C\!P}$ asymmetry is measured in two $D_s^-$ meson decay modes, ${D_s^- \to K^-K^+\pi^-}$ and ${D_s^- \to \pi^-\pi^+\pi^-}$. The combined result, $\langle A^s_{\rm untagged}\rangle = ( -1.4 \pm 5.9\,\rm{(stat)} \pm 1.1\,\rm{(syst)}) \times 10^{-3}$, is consistent with the Standard Model expectation and provides a direct constraint on new physics in tree-level $b$-hadron decays.

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LHCb collaboration, R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, C. A. Aidala, Z. Ajaltouni, S. Akar, K. Akiba, P. Albicocco, J. Albrecht, R. Aleksiejunas, F. Alessio, P. Alvarez Cartelle, R. Amalric, S. Amato, J. L. Amey, Y. Amhis, L. An, L. Anderlini, M. Andersson, P. Andreola, M. Andreotti, S. Andres Estrada, A. Anelli, D. Ao, C. Arata, F. Archilli, Z. Areg, M. Argenton, S. Arguedas Cuendis, L. Arnone, M. Artuso, E. Aslanides, R. Ataíde Da Silva, M. Atzeni, B. Audurier, J. A. Authier, D. Bacher, I. Bachiller Perea, S. Bachmann, M. Bachmayer, J. J. Back, Z. B. Bai, P. Baladron Rodriguez, V. Balagura, A. Balboni, W. Baldini, Z. Baldwin, L. Balzani, H. Bao, J. Baptista de Souza Leite, C. Barbero Pretel, M. Barbetti, I. R. Barbosa, R. J. Barlow, M. Barnyakov, S. Barsuk, W. Barter, J. Bartz, S. Bashir, B. Batsukh, P. B. Battista, A. Bavarchee, A. Bay, A. Beck, M. Becker, F. Bedeschi, I. B. Bediaga, N. A. Behling, S. Belin, A. Bellavista, I. Belov, I. Belyaev, G. Benane, G. Bencivenni, E. Ben-Haim, R. Bernet, A. Bertolin, F. Betti, J. Bex, O. Bezshyyko, S. Bhattacharya, M. S. Bieker, N. V. Biesuz, A. Biolchini, M. Birch, F. C. R. Bishop, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J. E. Blank. 2026-03-11. First measurement of the decay-time-integrated $C\!P$ asymmetry in $B_s^0 \to D_s^- \pi^+$ decays. https://doi.org/10.1103/ljtv-y278

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