# Towards $\overline{B}\to {X}_s\gamma$ at the NNLO in QCD without interpolation in m$_{c}$

Misiak, Miko-laj; Rehman, Abdur 1; Steinhauser, Matthias 1
1 Institut für Theoretische Teilchenphysik (TTP), Karlsruher Institut für Technologie (KIT)

## Abstract:

Strengthening constraints on new physics from the $\overline{B}\to {X}_s\gamma$ branching ratio requires improving accuracy in the measurements and the Standard Model predictions. To match the expected Belle-II accuracy, Next-to-Next-to-Leading Order (NNLO) QCD corrections must be calculated without the so-far employed interpolation in the charm- quark mass m$_{c}$. In the process of evaluating such corrections at the physical value of mc, we have finalized the part coming from diagrams with closed fermion loops on the gluon lines that contribute to the interference of the current-current and photonic dipole operators. We confirm several published results for corrections of this type, and supplement them with a previously uncalculated piece. Taking into account the recently improved estimates of non-perturbative contributions, we find ℬ$_{sγ}$ = (3.40±0.17)×10$^{-4}$ and R$_{γ}$≡B$_{(s+d)γ}$/B$_{cℓ\overline{v}}$ = (3.35 ± 0.16) × 10$^{-3}$ for E$_{γ}$> 1.6 GeV in the decaying meson rest frame.

 Zugehörige Institution(en) am KIT Institut für Theoretische Teilchenphysik (TTP) Publikationstyp Zeitschriftenaufsatz Publikationsmonat/-jahr 06.2020 Sprache Englisch Identifikator ISSN: 1029-8479 KITopen-ID: 1000122716 Erschienen in Journal of high energy physics Verlag Scuola Internazionale Superiore di Studi Avanzati (SISSA) Heft 6 Seiten Art.Nr. 175 Vorab online veröffentlicht am 29.06.2020 Nachgewiesen in DimensionsScopus
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