arXiv · 2512.09288
Precision measurement of CP violation and branching fractions in $B^{\pm} \to K^0_{\mathrm{S}} h^{\pm}$ $(h = \pi, K)$ decays and search for the rare decay $B_c^{\pm} \to K^0_{\mathrm{S}} K^{\pm}$
Abstract
The decay $B^{\pm} \to K^0_{\mathrm{S}} \pi^{\pm}$, with a $CP$ asymmetry expected to be close to zero in the Standard Model, is theoretically clean and sensitive to potential new physics. An analysis of the decays $B^{\pm} \to K^0_{\mathrm{S}} \pi^{\pm}$ and $B^{\pm} \to K^0_{\mathrm{S}} K^{\pm}$ is performed using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of $13\,\mathrm{TeV}$, corresponding to an integrated luminosity of $5.4\,\mathrm{fb}^{-1}$. The \CP asymmetries are determined to be ${\cal A}^{CP}(B^{\pm} \to K^0_{\mathrm{S}} \pi^{\pm})=-0.028\pm 0.009\pm 0.009$ and ${\cal A}^{CP}(B^{\pm} \to K^0_{\mathrm{S}} K^{\pm})=0.118\pm 0.062 \pm 0.031$, and the branching fraction ratio is measured to be ${\cal B}(B^{\pm} \to K^0_{\mathrm{S}} K^{\pm})/{\cal B}(B^{\pm} \to K^0_{\mathrm{S}} \pi^{\pm})=0.055\pm 0.004 \pm 0.002$, where the first uncertainties are statistical and the second are systematic. These results are the most precise measurements of these quantities to date. A search for the rare decay $B_c^{\pm} \to K^0_{\mathrm{S}} K^{\pm}$ is also performed. No significant signal is observed, and the upper limit on the product of the branching fraction ratio ${\cal B}(B_c^{\pm} \to K^0_{\mathrm{S}} K^{\pm})/{\cal B}(B^{\pm} \to K^0_{\mathrm{S}} \pi^{\pm})$ and the fragmentation-fraction ratio $f_c/f_u$ is set to be 0.015 (0.016) at the 90\% (95\%) confidence level.
Explore related subjects
Keep this discovery
R. Aaij, 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, M. Akthar, 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, A. Artamonov, 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, 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. Bay, A. Beck, M. Becker, F. Bedeschi, I. B. Bediaga, N. A. Behling, S. Belin, A. Bellavista, K. Belous, I. Belov, I. Belyaev, G. Benane, G. Bencivenni, E. Ben-Haim, A. Berezhnoy, R. Bernet, S. Bernet Andres, 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. 2025-12-10. Precision measurement of CP violation and branching fractions in $B^{\pm} \to K^0_{\mathrm{S}} h^{\pm}$ $(h = \pi, K)$ decays and search for the rare decay $B_c^{\pm} \to K^0_{\mathrm{S}} K^{\pm}$. https://doi.org/10.1103/vtgl-j97l
Cite the original work for its findings. Save a collection to share your selection of sources.