Talk (non-conference) (Other)

FZJ-2024-06523

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Study of radiative leptonic decays from first principles

Giusti, D. (Corresponding author)FZJ*

2024

Abstract: In the region of hard photon energies, radiative leptonic decays represent important probes of the internal structure of hadrons. Moreover, radiative decays can provide independent determinations of Cabibbo-Kobayashi-Maskawa matrix elements with respect to purely leptonic or semileptonic channels. Prospects for a precise determination of leptonic decay rates with emission of a hard photon are particularly interesting, especially for the decays of heavy mesons for which currently only model-dependent predictions, based on QCD factorization and sum rules, are available to compare with existing experimental data. We present a non-perturbative lattice calculation of the structure-dependent form factors which contribute to the amplitudes for the radiative decays $H \to \ell \nu_\ell \gamma$, where H is a charged pseudoscalar meson. With moderate statistics, thanks to the use of improved estimators, we are able to provide rather precise, first-principles results for the form factors in the full kinematical (photon-energy) range. Our continuum-extrapolated lattice determinations may then be employed to compute the differential decay rate and the corresponding branching fraction and make comparisons with existing experimental data.

---

Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 5111 - Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups (POF4-511) (POF4-511)
2. MUON - Lattice determination of the muon's anomalous magnetic moment (101054515) (101054515)

Appears in the scientific report 2024

---