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

TL;DR

This study uses lattice QCD simulations with physical strange and charm quarks to compute the mass spectra of $D_s$ and $\Omega_c$ baryons, matching experimental data and predicting properties of unobserved states.

Contribution

First lattice QCD calculation with $N_f=2+1+1$ domain-wall quarks accurately predicting $D_s$ and $\Omega_c$ spectra, including unobserved charmed baryons.

Findings

Mass spectra agree with experimental values

Predicted mass of $\Omega_c(3000)$ matches observed data

Determined $J^P$ of $\Omega_c(3000)$ as $1/2^-$

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^- $.