Masses and decay constants of $B_c^{(\ast )}$ mesons with $N_f=2+1+1$ twisted mass fermions

Abstract

We present a preliminary lattice determination of the masses and decay constants of the pseudoscalar and vector mesons $B_c$ and $B_c^{\ast }$. Our analysis is based on the gauge configurations produced by the European Twisted Mass Collaboration with $N_f=2+1+1$ flavors of dynamical quarks. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV. Heavy-quark masses are simulated directly on the lattice up to $\sim 3$ times the physical charm mass. The physical b-quark mass is reached using the ETMC ratio method. Our preliminary results are: $M_{B_c}=6341(60)$ MeV, $f_{B_c}=396(12)$ MeV, $M_{B_c^{\ast }}/M_{B_c}=1.0037(39)$ and $f_{B_c^{\ast }}/f_{B_c}=0.987(7)$.

7 pages, 3 figures, 1 table; contribution to the proceedings of the XXXVI Int'l Workshop on Lattice Field Theory (LATTICE2018), July 22-28, 2018, East Lansing, Michigan State University (Michigan, USA)