Precisely determining the ground state mass of Spin-3/2 $Ω_{ccc}$ baryon from Lattice QCD

TL;DR

This paper determines the ground-state masses of the triply charmed baryon Ω_{ccc} in both parity channels using lattice QCD with six $N_f=2+1+1$ HISQ ensembles and two valence actions (Overlap and HISQ). By forming heavy-quark mass-subtracted splittings and performing continuum extrapolations with $a^2$ (and $a^4$) terms, then adding the experimental $M_{J/ψ}$ contribution, the authors obtain $M_{Ω_{ccc}}(3/2^+)=4793(5)^{+11}_{-8}$ MeV and $M_{Ω_{ccc}}(3/2^-)=5094(12)^{+19}_{-17}$ MeV, the most precise lattice results to date. The study demonstrates cross-method consistency between Overlap and HISQ valence quarks on fine lattices, validates hyperfine splittings against experimental expectations, and provides a robust benchmark for forthcoming experimental measurements and theoretical studies of confinement in triply heavy systems. Overall, the results advance the precision frontier in heavy baryon spectroscopy and offer critical targets for high-luminosity facilities seeking to observe the Ω_{ccc}.

Abstract

We present the most precise determination to date of the ground-state masses of the triply charmed baryons with both parities, obtained by continuum extrapolation and fully addressing the systematic uncertainties. The calculations are performed on six $N_f=2+1+1$ HISQ ensembles, generated by the MILC collaboration, with two complementary setups for the valence charm action, one using the HISQ action and the other using the overlap fermion action. Our prediction for the mass of the lowest two triply charmed spin-3/2 baryons are: $M_{Ω_{ccc}} (3/2^{+}) = 4793 (5) \left(^{+11}_{-8}\right)$ MeV, and $M_{Ω_{ccc}} (3/2^{-}) = 5094 (12) \left(^{+19}_{-17}\right)$ MeV.

Figures (3)

• Figure 1: Summary of results for the ground-state masses of the $\Omega_{ccc}(3/2^{+})$ and $\Omega_{ccc}(3/2^{-})$ baryons from various lattice calculations. Results that include a continuum extrapolation are shown as orange circles, while those obtained at a single lattice spacing are indicated by blue circles. Filled circles correspond to the $3/2^{+}$ state, whereas open circles denote the $3/2^{-}$ state. Our continuum extrapolated values are highlighted in red, and the accompanying blue band is drawn through the red point to aid visual comparison with the other determinations.
• Figure 2: Dependence of the extracted mass values (in lattice units) on the choice of $t_{\min}$, on the $64^3 \times 192$ Overlap ensemble and the $96^3 \times 288$ HISQ ensemble.
• Figure 3: Continuum extrapolation of $\Delta M_{\Omega_{ccc}}$ for the positive (left) and negative (right) parity channels. Different fit forms are displayed with the color codes indicated in the legends. The shaded bands denote the $1\sigma$ uncertainties obtained from bootstrap resampling. The stars mark the corresponding continuum limits, while the red filled squares indicate the final estimates, obtained from a symmetrized average of the linear extrapolations from the Overlap and HISQ data; the enlarged error bars incorporate the spread across the alternative fit forms.