Lattice QCD study of $B_s\to D_s\ell {\bar{\nu }}_{\ell }$ decay near zero recoil

Abstract

We study the hadronic matrix elements describing the $B_s\to D_s\ell {\bar{\nu }}_{\ell }$ decay in and beyond the Standard Model. By using the twisted mass QCD on the lattice with $N_f=2$ dynamical flavors we compute the normalization ${\mathcal{G}}_s(1)$ of the form factor dominating $B_s\to D_s\ell {\bar{\nu }}_{\ell }$ in the SM. We also make the first lattice determination of $F_0(q^2)/F_{+}(q^2)$ and $F_T(q^2)/F_{+}(q^2)$ near zero recoil (near $q_{\max }^2$). We briefly discuss the non-strange case $B\to D\ell {\bar{\nu }}_{\ell }$ as well.

Comments: presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, Germany