Most Strange Dibaryon from Lattice QCD

TL;DR

This study uses advanced lattice QCD simulations to investigate the most strange dibaryon, the $ ext{ΩΩ}$ system, revealing it to be an attractive near-threshold bound state with potential experimental observability.

Contribution

First lattice QCD calculation of the $ ext{ΩΩ}$ dibaryon near physical pion mass showing its attractive nature and near-unitary behavior.

Findings

The $ ext{ΩΩ}$ system has a scattering length of about 4.6 fm.

The effective range of the interaction is approximately 1.27 fm.

The binding energy of the $ ext{ΩΩ}$ system is around 1.6 MeV.

Abstract

The $\Omega\Omega$ system in the $^1S_0$ channel (the most strange dibaryon) is studied on the basis of the (2+1)-flavor lattice QCD simulations with a large volume (8.1 fm)$^3$ and nearly physical pion mass $m_{\pi}\simeq 146$ MeV at a lattice spacing $a\simeq 0.0846$ fm. We show that lattice QCD data analysis by the HAL QCD method leads to the scattering length $a_0 = 4.6 (6)(^{+1.2}_{-0.5}) {\rm fm}$, the effective range $r_{\rm eff} = 1.27 (3)(^{+0.06}_{-0.03}) {\rm fm}$ and the binding energy $B_{\Omega \Omega} = 1.6 (6) (^{+0.7}_{-0.6}) {\rm MeV}$. These results indicate that the $\Omega\Omega$ system has an overall attraction and is located near the unitary regime. Such a system can be best searched experimentally by the pair-momentum correlation in relativistic heavy-ion collisions.