Year: 2026
Type: preprint
Abstract: The inclusive weak radiative $B$-meson decay provides important constraints on many popular extensions of the Standard Model. Some of the numerically relevant Next-to-Next-to-Leading-Order QCD corrections to its branching ratio have so far been evaluated using an interpolation in the charm quark mass between the $m_c=0$ and $m_c \gg m_b$ limits. In the current paper, we present their determination for the physical value of $m_c$, which required calculating hundreds of four-loop propagator diagrams with unitarity cuts and two mass scales. Our final result for the CP- and isospin-averaged branching ratio reads ${\mathcal B}_{s γ}^{\rm SM} = (3.54 \pm 0.14)\times 10^{-4}$ for $E_γ> 1.6\,{\rm GeV}$ in the decaying meson rest frame. It is in good agreement with the current Particle Data Group average ${\mathcal B}_{s γ}^{\rm exp} = (3.49 \pm 0.19)\times 10^{-4}$.
Source: arXiv (Cornell University)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W7204872620