$H$ dibaryon and its cousins from SU(6)-constrained baryon-baryon interaction

Abstract

We constrain the $S$-wave baryon-baryon interaction using SU(6) symmetry within a nonrelativistic effective field theory. The most general leading-order Lagrangian contains two independent parameters, which we determine using physical $NN$ and lattice QCD $\Omega\Omega$ scattering lengths. This framework allows for parameter-free predictions in the strangeness $S=-2$ sector relevant to the $H$ dibaryon. Solving the coupled-channel scattering problem, we identify two bound states below the $\Lambda\Lambda$ threshold, one deeply bound and one shallow, along with resonances near the $\Sigma\Sigma$ and $\Sigma^*\Sigma^*$ thresholds. We demonstrate that these poles result in distinct enhancements in $\Lambda\Lambda$ invariant mass distributions, suggesting that the $H$ dibaryon exists as a multichannel bound state and providing clear signatures for experimental verification.