Matthias König, The Simplest B Decay, Precisely

Thursday 12 Feb 2026, 14:30 → 15:30 Europe/Rome

Sala Wataghin (Vecchio Edificio)

The exclusive, leptonic decay $B^-\to\ell^-\bar\nu_\ell$ is a deceptively simple process, but upon closer inspection reveals itself to be a surprisingly complicated problem once radiative QED corrections are included. Being a chirally suppressed channel, it receives contributions from a wealth of different scales. To properly address all of them, a wide range of effective theories is needed, including HQET, SCET, χPT and more. In this talk I will sketch the derivation of a QED × QCD factorization theorem, explain the various EFT constructions, their subtleties and present our phenomenological predictions.