Three-loop QCD corrections to the heavy-to-light form factors

by Sudeepan Datta (PSI, Villigen)

Monday 20 Oct 2025, 16:00 → 17:00 Europe/Berlin

D308 (ENC)

In this talk, I will begin by outlining the physics motivation for computing perturbative corrections to form factors for processes involving heavy-to-light transitions. I will then provide an overview of the standard workflow used in diagrammatic calculations of radiative corrections, highlighting the role of available automated tools at various stages. 

The main part of the talk will focus on our calculation of the three-loop QCD corrections to these form factors, using the top-decay process  $t \rightarrow b\, W^*$ as a prototype. We specifically consider the leading-colour contributions, the complete set of light-fermion contributions, and the diagrams containing two heavy-fermion loops. All relevant master integrals are evaluated analytically using the method of differential equations, and the results are expressed in terms of harmonic and generalized harmonic polylogarithms.

Finally, we use these three-loop results to study the infra-red (IR) structure that arises in their high-energy limit, and correspond it with the known IR structures of the massless and massive form factors at three loops.