Singly and Doubly Charmed J=1/2 Baryon Spectrum from Lattice QCD

TL;DR

This study uses lattice QCD with relativistic charm quarks and domain-wall light quarks to compute and predict masses of singly and doubly charmed baryons, achieving good agreement with experimental data.

Contribution

It provides the first lattice QCD calculations of the charmed baryon spectrum using relativistic heavy-quark actions and predicts the \

Findings

Mass of c baryon: 3665  17  14 +0 -78 MeV

Mass splitting between c and c : 98  9  22  13 MeV

Predicted c  baryon mass: 3763  19  26 +13 -79 MeV

Abstract

We compute the masses of the singly and doubly charmed baryons in full QCD using the relativistic Fermilab action for the charm quark. For the light quarks we use domain-wall fermions in the valence sector and improved Kogut-Susskind sea quarks. We use the low-lying charmonium spectrum to tune our heavy-quark action and as a guide to understanding the discretization errors associated with the heavy quark. Our results are in good agreement with experiment within our systematics. For the \Xi_{cc}, we find the isospin-averaged mass to be M_{\Xi_{cc}} = 3665 +/- 17 +/- 14 +0 -78 MeV; the three given uncertainties are statistical, systematic and an estimate of lattice discretization errors, respectively. In addition, we predict the mass splitting of the (isospin-averaged) spin-1/2 \Omega_{cc} with the \Xi_{cc} to be M_{\Omega_{cc}} - M_{\Xi_{cc}} = 98 +/- 9 +/- 22 +/- 13 MeV (in this mass splitting, the leading discretization errors are also suppressed by SU(3) symmetry). Combining this splitting with our determination of M_{\Xi_{cc}} leads to our prediction of the spin-1/2 \Omega_{cc} mass, M_{\Omega_{cc}} = 3763 +/- 19 +/- 26 +13 -79 MeV.