Beauty mesons in $N_f=2+1+1+1 $ lattice QCD with exact chiral symmetry

We present the first study of $N_f=2+1+1+1$ lattice QCD with domain-wall quarks. The $(b, c, s)$ quarks are physical, while the $(u, d)$ quarks are heavier than their physical masses, with the pion mass $ \sim 700 $ MeV. The gauge ensemble is generated by hybrid Monte Carlo simulation with the Wilson gauge action for the gluons, and the optimal domain-wall fermion action for the quarks. Using point-to-point quark propagators, we measure the time-correlation functions of quark-antiquark meson interpolators with quark contents $\bar b b$, $\bar b c$, $\bar b s$, and $ \bar c c$, and obtain the masses of the low-lying mesons. They are in good agreement with the experimental values, plus some predictions which have not been observed in experiments. Moreover, we also determine the masses of $(b, c, s)$ quarks.