$\Lambda\Lambda$ and N$\Xi$ interactions from Lattice QCD near the physical point

TL;DR

This study uses lattice QCD simulations near physical quark masses to analyze $\\Lambda\\\Lambda$ and $N\\Xi$ interactions, revealing weak attraction in $\\Lambda\\Lambda$ and near-unitarity in $N\\Xi$, with implications for hypernuclei and nuclear collisions.

Contribution

First lattice QCD analysis of $\\Lambda\\Lambda$ and $N\\Xi$ interactions near physical quark masses using the HAL QCD method, providing detailed potentials and phase shifts.

Findings

Weak attraction in $\\Lambda\\Lambda$ interaction, no bound dihyperon.

$N\\Xi$ interaction in spin-singlet, isospin-singlet channel is near unitarity.

Implications for strangeness=-2 hypernuclei and baryon correlations in collisions.

Abstract

The $S$-wave $\Lambda\Lambda$ and $N \Xi$ interactions are studied on the basis of the (2+1)-flavor lattice QCD simulations close to the physical point ($m_\pi \simeq 146{\rm{MeV}}$ and $m_K \simeq 525{\rm{MeV}}$). Lattice QCD potentials in four different spin-isospin channels are extracted by using the coupled-channel HAL QCD method and are parametrized by analytic functions to calculate the scattering phase shifts. The $\Lambda \Lambda$ interaction at low energies shows only a weak attraction, which does not provide a bound or resonant dihyperon. The $N\Xi$ interaction in the spin-singlet and isospin-singlet channel is most attractive and lead the $N\Xi$ system near unitarity. Relevance to the strangeness=$-2$ hypernuclei as well as to two-baryon correlations in proton-proton, proton-nucleus and nucleus-nucleus collisions is also discussed.