Erlangen 2026 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 8: Flavour Physics I
T 8.3: Vortrag
Montag, 16. März 2026, 16:45–17:00, KH 01.011
Two-loop corrections to the penguin amplitude a6 in QCD factorization — Guido Bell1, Kevin Brune2, Tobias Huber1, and •Sandra Kvedaraite1 — 1Universität Siegen, Siegen, Germany — 2Johannes Gutenberg-Universität Mainz, Mainz, Germany
The QCD penguin amplitude plays a central role in understanding CP violation in non-leptonic B-meson decays. It arises from the loop-induced weak-interaction process b → D ∑q=u, d, s qq, where D=d, s, and can be expressed in terms of the leading-power amplitude a4 and the higher-twist amplitude a6. Even though a6 is power-suppressed in the heavy-quark limit, chiral enhancement makes it numerically comparable to a4, making it relevant for branching ratios and CP-violating observables. While a4 is known to next-to-next-to-leading order, a6 is currently available only at next-to-leading order. In this talk, I will present recent progress towards the two-loop calculation of a6 in the QCD factorization approach to non-leptonic B-meson decays.
Keywords: QCD factorization; Non-leptonic B decays; Penguin amplitudes; CP violation; NNLO corrections