The \boldmath$B\to D^{\ast }\ell \nu$ semileptonic decay at nonzero recoil and its implications for $|V_{cb}|$ and $R(D^{\ast })$

Abstract

We present nearly final results from our analysis of the form factors for $B\to D^{\ast }\ell \nu$ decay at nonzero recoil. Our analysis includes 15 MILC asqtad ensembles with $N_f=2+1$ flavors of sea quarks and lattice spacings ranging from $a\approx 0.15$ fm down to $0.045$ fm. The valence light quarks employ the asqtad action, whereas the $b$ and $c$ quarks are treated using the Fermilab action. We discuss the impact that our results will have on $|V_{cb}|$ and $R(D^{\ast })$.

Comments: 7 pages, 3 figures. Proceedings of the 37th International Symposium on Lattice Field Theory - Lattice 2019, Wuhan (China)