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  • Open Access

CKM blind spot: Probing b-column rescaling with kaons

Avital Dery*

  • CERN, Theoretical Physics Department, Geneva, Switzerland

  • *Contact author: avital.dery@cern.ch
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Phys. Rev. D 114, 055058 – Published 30 September, 2026

DOI: https://doi.org/10.1103/hynj-9y11

Abstract

Cabibbo–Kobayashi–Maskawa unitarity triangle constraints are insensitive to new physics scenarios in which the b column is uniformly rescaled. This is because B physics data overconstrain the angles of the (bd) unitarity triangle, but only calibrate its normalization. We identify this flat direction and derive model-independent constraints on the rescaling. We find that |ϵK| already constrains the rescaling at the same level as the direct measurement of the b-column normalization, with current data allowing for O(4%) deviations. Projected inputs promote the kaon sector to be the leading probe. A toy model employing mixing with a vectorlike up-type singlet provides a proof of principle for a possible UV realization.

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References (46)

  1. V. Chobanova, G. D’Ambrosio, T. Kitahara, M. Lucio Martinez, D. Martinez Santos, I. S. Fernandez, and K. Yamamoto, J. High Energy Phys. 05 (2018) 024.
  2. A. Dery and M. Ghosh, J. High Energy Phys. 03 (2022) 048.
  3. G. D’Ambrosio, F. Mahmoudi, and S. Neshatpour, J. High Energy Phys. 02 (2024) 166.
  4. G. D’Ambrosio, A. M. Iyer, F. Mahmoudi, and S. Neshatpour, Phys. Lett. B 855, 138824 (2024).
  5. G. D’Ambrosio, A. M. Iyer, F. Mahmoudi, and S. Neshatpour, arXiv:2512.16903.
  6. J. Charles, A. Hocker, H. Lacker, S. Laplace, F. R. Le Diberder, J. Malcles, J. Ocariz, M. Pivk, and L. Roos (CKMfitter Group Collaboration), Eur. Phys. J. C 41, 1 (2005).
  7. L. Wolfenstein, Phys. Rev. Lett. 51, 1945 (1983).
  8. A. J. Buras, M. E. Lautenbacher, and G. Ostermaier, Phys. Rev. D 50, 3433 (1994).
  9. A. J. Buras, P. Gambino, M. Gorbahn, S. Jager, and L. Silvestrini, Phys. Lett. B 500, 161 (2001).
  10. A. Dery, Phys. Rev. D 112, 053005 (2025).
  11. S. Navas et al. (Particle Data Group Collaboration), Phys. Rev. D 110, 030001 (2024).
  12. LHC Top Working Group summary plots, single top quark production (2023), https://twiki.cern.ch/twiki/bin/view/LHCPhysics/LHCTopWGSummaryPlots.
  13. B. Grzadkowski, M. Iskrzynski, M. Misiak, and J. Rosiek, J. High Energy Phys. 10 (2010) 085.
  14. A. Efrati, A. Falkowski, and Y. Soreq, J. High Energy Phys. 07 (2015) 018.
  15. G. Aad et al. (ATLAS Collaboration), J. High Energy Phys. 07 (2024) 163.
  16. K. Lee et al. (CMS Collaboration), J. High Energy Phys. 12 (2021) 083.
  17. G. Aad et al. (ATLAS Collaboration), Phys. Rev. D 108, 032019 (2023).
  18. F. del Aguila, J. A. Aguilar-Saavedra, and R. Miquel, Phys. Rev. Lett. 82, 1628 (1999).
  19. Y. Nir and D. J. Silverman, Phys. Rev. D 42, 1477 (1990).
  20. J. Brod, M. Gorbahn, and E. Stamou, Proc. Sci. BEAUTY2020 (2021) 056 [arXiv:2105.02868].
  21. A. Dery, M. Ghosh, Y. Grossman, and S. Schacht, J. High Energy Phys. 07 (2021) 103.
  22. J. Brod and E. Stamou, J. High Energy Phys. 05 (2023) 155.
  23. J. Fry et al. (KOTO Collaboration), arXiv:2501.14827.
  24. G. D’Ambrosio, A. Dery, Y. Grossman, T. Kitahara, R. Marchevski, D. Martínez Santos, and S. Schacht, J. High Energy Phys. 09 (2025) 190.
  25. W. Altmannshofer et al. (Belle-II Collaboration), Prog. Theor. Exp. Phys. 2019, 123C01 (2019); 2020, 029201(E) (2020).
  26. P. Azzi et al., CERN Yellow Rep. Monogr. 7, 1 (2019).
  27. R. Aaij et al. (LHCb Collaboration), arXiv:1808.08865.
  28. A. S. Kronfeld et al. (USQCD Collaboration), arXiv:2207.07641.
  29. X. Chang (NA62 Collaboration), in 60th Rencontres de Moriond on Electroweak Interactions and Unified Theories: Moriond EW 2026 (2026), arXiv:2604.12649.
  30. J. Aebischer et al., J. Phys. G 52, 100501 (2025).
  31. J. Brod, M. Gorbahn, and E. Stamou, Phys. Rev. Lett. 125, 171803 (2020).
  32. J. Brod, S. Kvedaraite, Z. Polonsky, and A. Youssef, J. High Energy Phys. 12 (2022) 014.
  33. T. Inami and C. S. Lim, Prog. Theor. Phys. 65, 297 (1981); 65, 1772(E) (1981).
  34. Y. Aoki et al. (Flavour Lattice Averaging Group (FLAG) Collaboration), Phys. Rev. D 113, 014508 (2026).
  35. Z. Bai, N. H. Christ, J. M. Karpie, C. T. Sachrajda, A. Soni, and B. Wang, Phys. Rev. D 109, 054501 (2024).
  36. A. J. Buras, D. Buttazzo, J. Girrbach-Noe, and R. Knegjens, J. High Energy Phys. 11 (2015) 033.
  37. B. Belfatto, R. Beradze, and Z. Berezhiani, Eur. Phys. J. C 80, 149 (2020).
  38. B. Belfatto and Z. Berezhiani, J. High Energy Phys. 10 (2021) 079.
  39. G. C. Branco, J. T. Penedo, P. M. F. Pereira, M. N. Rebelo, and J. I. Silva-Marcos, J. High Energy Phys. 07 (2021) 099.
  40. G. Aad et al. (ATLAS Collaboration), Phys. Lett. B 854, 138743 (2024).
  41. A. Tumasyan et al. (CMS Collaboration), J. High Energy Phys. 07 (2023) 020.
  42. G. Aad et al. (ATLAS Collaboration), J. High Energy Phys. 08 (2023) 153.
  43. A. Hayrapetyan et al. (CMS Collaboration), Phys. Rev. D 110, 072012 (2024).
  44. L. Lavoura and J. P. Silva, Phys. Rev. D 47, 2046 (1993).
  45. J. M. Alves, G. C. Branco, A. L. Cherchiglia, C. C. Nishi, J. T. Penedo, P. M. F. Pereira, M. N. Rebelo, and J. I. Silva-Marcos, Phys. Rep. 1057, 1 (2024).
  46. K. Agashe, R. Contino, L. Da Rold, and A. Pomarol, Phys. Lett. B 641, 62 (2006).

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Phys. Rev. D 114, 055058– Published 30 September, 2026
  • Received 30 July 2026
  • Accepted 8 September 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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