Resummation of double logarithms from soft-fermion exchange

Philipp Böer (CERN, Geneva)

Jul 30. 2026, 10:00 — 10:40

It is well known that perturbative QCD corrections to scattering processes contain large double logarithms in the high-energy limit. At leading power, these are typically induced by soft-gluon exchanges, and their all-order structure is well understood. At subleading power, however, double logarithms often arise from soft-fermion exchanges and exhibit a richer, more intricate structure. I will discuss recent advances in the all-order resummation of these corrections, ranging from simple QED processes such as muon–electron backward scattering to heavy-to-light B-meson form factors. Within the framework of Soft-Collinear Effective Theory, the theoretical description of these corrections is complicated by the fact that the factorisation of subleading soft and collinear contributions gives rise to endpoint-divergent convolution integrals. By implementing a physical cutoff, I will present a systematic framework for their resummation based on asymptotic limits of anomalous dimensions of the underlying effective operators.

Further Information
Venue:
ESI Schrödinger Lecture Hall
Associated Event:
New Paradigms for Harnessing Quantum Field Theory at Colliders (Thematic Programme)
Organizer(s):
Alessandro Broggio (U of Vienna)
André H. Hoang (U of Vienna)
Bianka Meçaj (LANL, Los Alamos)
Simon Plätzer (U of Graz)
Massimiliano Procura (U of Vienna)
Rudi Rahn (U of Vienna)
Malin Sjödahl (Lund U)
Iain W. Stewart (MIT, Cambridge)