On the $B^{{\ast }^{\prime }}\to B$ transition

Abstract

We present a first $N_{\mathrm{f}}=2$ lattice estimate of the hadronic coupling $g_{12}$ which parametrizes the strong decay of a radially excited $B^{\ast }$ meson into the ground state $B$ meson at zero recoil. We work in the static limit of Heavy Quark Effective Theory (HQET) and solve a Generalised Eigenvalue Problem (GEVP), which is necessary for the extraction of excited state properties. After an extrapolation to the continuum limit and a check of the pion mass dependence, we obtain $g_{12}=-0.17(4)$.

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