We perform the first global fit to inclusive $B\to X_s\gamma$ measurements using a model-independent treatment of the nonperturbative $b$-quark distribution function, with next-to-next-to-leading logarithmic resummation and $\mathcal{O}({\alpha }_s^2)$ fixed-order contributions. The normalization of the $B\to X_s\gamma$ decay rate, given by $|C_7^{\mathrm{incl}}{V}_{tb}{V}_{ts}^{*}{|}^2$, is sensitive to physics beyond the standard model (SM). We determine $|C_7^{\mathrm{incl}}{V}_{tb}{V}_{ts}^{*}|=(14.77\pm 0.51_{\mathrm{fit}}\pm 0.59_{\text{theory}}\pm 0.08_{\text{param}})\times {10}^{-3}$, in good agreement with the SM prediction, and the $b$-quark mass $m_b^{1S}=(4.750\pm 0.027_{\mathrm{fit}}\pm 0.033_{\text{theory}}\pm 0.003_{\text{param}})\mathrm{GeV}$. Our results suggest that the uncertainties in the extracted $B\to X_s\gamma$ rate have been underestimated by up to a factor of 2, leaving more room for beyond-SM contributions.

• Received 22 December 2020
• Revised 30 April 2021
• Accepted 24 June 2021

DOI:https://doi.org/10.1103/PhysRevLett.127.102001

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.

Published by the American Physical Society