Exclusive charmless B decays: Towards a factorization framework for power-corrections

by Philipp Böer

Monday 30 Oct 2023, 14:00 → 16:00 Europe/Zurich

4/3-006 - TH Conference Room (CERN)

In this talk, I will discuss recent progress in the theoretical treatment of power corrections for charmless exclusive B decays within the framework of soft-collinear EFT.

For several reasons, the treatment of power corrections is a complicated problem. First, they typically involve large operator bases with many novel non-perturbative functions.
Using the example of so-called weak annihilation amplitudes for non-leptonic decays, I will discuss the systematic matching onto SCET, and show that in particular soft physics becomes qualitatively different compared to the leading term in the 1/m_b expansion.

In the second part, I will focus on the resummation of double-logarithms in B_c -> eta_c transition form factors at large hadronic recoil.
Assuming the scale hierarchy m_b >> m_c >> Lambda_QCD, this perturbative setup defines one of the simplest examples to study the problem of endpoint singularities appearing in the factorization of exclusive B-decay amplitudes.
Using diagrammatic (non-EFT) techniques, I will explain that the resummation proceeds via a novel type of integral equations.
They reflect a peculiar interplay of ``endpoint logarithms'' arising from soft-quark exchanges, as well as standard Sudakov-type soft-gluon corrections.

Boeer_CERN.pdf