We calculate the low-lying spectrum of charmed baryons in lattice QCD on the ${32}^3\times 64$, $N_f=2+1$ PACS-CS gauge configurations at the almost physical pion mass of $\sim 156\mathrm{MeV}/c^2$. By employing a set of interpolating operators with different Dirac structures and quark-field smearings for the variational analysis, we extract the ground and first few excited states of the spin-$1/2$ and spin-$3/2$, singly, doubly, and triply charmed baryons. Additionally, we study the ${\mathrm{\Xi }}_c\text{−}{\mathrm{\Xi }}_c^{\prime }$ mixing and the operator dependence of the excited states in a variational approach. We identify several states that lie close to the experimentally observed excited states of the ${\mathrm{\Sigma }}_c$, ${\mathrm{\Xi }}_c$ and ${\mathrm{\Omega }}_c$ baryons, including some of the ${\mathrm{\Xi }}_c$ states recently reported by LHCb. Our results for the doubly and triply charmed baryons are suggestive for future experiments.

• Received 19 April 2020
• Accepted 8 September 2020

DOI:https://doi.org/10.1103/PhysRevD.102.054513

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Published by the American Physical Society