Semileptonic B(s) decays are of great phenomenological interest because they allow to determine e.g. CKM matrix elements or test lepton flavor universality. Taking advantage of already existing lattice data, we demonstrate the analysis steps to extract the four form factors describing exclusive semileptonic Bs→Ds∗ℓνℓ decays using the narrow width approximation. Our data are based on RBC/UKQCD's set of 2+1 flavor gauge field ensembles with Shamir domain-wall fermion and Iwasaki gauge field action featuring inverse lattice spacings of a−1=1.785, 2.383, and 2.785 GeV as well as pion masses between 268 and 433 MeV. Light, strange and charm quarks are simulated using domain-wall fermions, whereas bottom quarks are generated with the relativistic heavy quark (RHQ) action.
@article{arxiv.2603.27879,
title = {Extracting $B_s\to D_s^*\ell\nu_\ell$ form factors},
author = {Anastasia Boushmelev and Matthew Black and Oliver Witzel},
journal= {arXiv preprint arXiv:2603.27879},
year = {2026}
}
Comments
10 pages, 1 table, 6 figures; contribution to the 42nd International Symposium on Lattice Field Theory, 2-8 November 2025, Tata Institute of Fundamental Research, Mumbai, India