Real radiative decays of heavy pseudoscalar mesons

Abstract

We report our ongoing lattice QCD study of radiative leptonic decays of the charged pseudoscalar mesons $D$, $D_s$, $B$, and $B_c\to \ell {\nu }_{\ell }\gamma$. We carry out our analysis on a single JLQCD ensemble with lattice spacing $a=0.044\text{fm}$. This work is a step towards a complete QCD+QED lattice calculation of these modes, aimed at reducing theoretical uncertainties in the extraction of $|V_{cd}|$ and $|V_{cs}|$ and providing first-principles estimates of the corresponding form factors in the $B$ sector.

Comments: 8 pages, 4 figures, 1 table, contribution to The 42nd International Symposium on Lattice Field Theory (LATTICE2025), 2-8 November 2025, Tata Institute of Fundamental Research, Mumbai, India