Erlangen 2026 – scientific programme

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T: Fachverband Teilchenphysik

T 8: Flavour Physics I

T 8.7: Talk

Monday, March 16, 2026, 17:45–18:00, KH 01.011

An effective hadronic field theory for B-meson decays at high recoil — •Jaime del Palacio Lirola, Thorsten Feldmann, and Jack Jenkins — University of Siegen

We construct an effective hadronic Lagrangian for heavy-meson decays into energetic pseudo-Goldstone bosons of chiral symmetry breaking, by exploring the interplay between two already existing Effective Field Theory frameworks: Heavy Hadron Chiral Perturbation Theory, and Soft-Collinear Effective Theory (SCET). In the new theory, the dynamical degrees of freedom are given by quasi-static heavy meson fields coupled to soft and collinear pions, kaons and η mesons. In this talk we focus on the matching of external heavy-to-light currents in SCET onto effective operators in the hadronic Lagrangian. From our result, we calculate the 1-loop corrections for the external current, which determines the non-analytic dependence on the light meson mass, known as “chiral logarithms”. This information is needed to perform the chiral extrapolation in lattice-QCD data, and to estimate SU(3) breaking effects in heavy-to-light form factors, both at large recoil (low q²).

Keywords: EFT; Chiral; SCET; Heavy; Decay