Mass Spectra of $D_s$ and $Ω_c$ in Lattice QCD with $N_f= 2+1+1$ Domain-Wall Quarks

Abstract: We perform hybrid Monte Carlo simulation of lattice QCD with $N_f=2+1+1 $ optimal domain-wall quarks on the $32^3 \times 64 $ lattice with lattice spacing $a \sim 0.06$ fm, and generate a gauge ensemble with physical $s$ and $c$ quarks, and pion mass $\sim 280 $ MeV. Using 2-quark (meson) and 3-quark (baryon) interpolating operators, the mass spectra of the lowest-lying states containing $s$ and $c$ quarks ($D_s$ and $\Omega_c$) are extracted \cite{Chen:2017kxr}, which turn out in good agreement with the high energy experimental values, together with the predictions of the charmed baryons which have not been observed in experiments. For the five new narrow $\Omega_c$ states observed by the LHCb Collaboration \cite{Aaij:2017nav}, the lowest-lying $\Omega_c(3000)$ agrees with our predicted mass $3015(29)(34)$ MeV of the lowest-lying $\Omega_c$ with $J^P = 1/2^{-}$. This implies that the $ J^P $ of $ \Omega_c(3000) $ is $ 1/2^- $.