Study of the $\Omega_{ccc}\Omega_{ccc}$ and $\Omega_{bbb}\Omega_{bbb}$ dibaryons in QCD Sum Rules

TL;DR

This study uses QCD sum rules to investigate the possible existence and properties of fully-heavy dibaryons, specifically $ ext{Ω}_{ccc} ext{Ω}_{ccc}$ and $ ext{Ω}_{bbb} ext{Ω}_{bbb}$, revealing their mass hierarchy and potential bound states.

Contribution

It introduces an efficient iterative dispersion relation method to compute complex five-loop diagrams and addresses divergence issues in the analysis of heavy dibaryons.

Findings

Scalar dibaryons are lighter than tensor ones.

The $ ext{Ω}_{ccc} ext{Ω}_{ccc}$ mass is just above the threshold.

The $ ext{Ω}_{bbb} ext{Ω}_{bbb}$ system may form bound states.

Abstract

The recent observation of a family of fully-charm tetraquark states by the LHCb, ATLAS and CMS Collaborations suggests the possible existence of fully-heavy dibaryons. In this work, we investigate the $\Omega_{ccc}\Omega_{ccc}$ and $\Omega_{bbb}\Omega_{bbb}$ dibaryons in both the $^1S_0$ and $^5S_2$ channels using the method of QCD sum rules. We employ the iterative dispersion relation (IDR) method to efficiently compute the massive five-loop banana diagrams that appear in these systems, and properly address the tricky small-circle divergence problem in the nonperturbative terms. Our analyses reveal that for both charm and bottom systems, the scalar dibaryon lies lower than its tensor counterpart. The mass of the scalar $\Omega_{ccc}\Omega_{ccc}$ dibaryon is found to be slightly above the $2\Omega_{ccc}$ mass threshold, while the $\Omega_{bbb}\Omega_{bbb}$ systems may form bound states.