Perhaps a Stable Dihyperon

Abstract

In the quark bag model, the same gluon-exchange forces which make the proton lighter than the $\ensuremath{\Delta}(1236)$ bind six quarks to form a stable, flavor-singlet (with strangeness of - 2) ${J}^{P}={0}^{+}$ dihyperon ($H$) at 2150 MeV. Another isosinglet dihyperon (${H}^{*}$) with ${J}^{P}={1}^{+}$ at 2335 MeV should appear as a bump in $\ensuremath{\Lambda}\ensuremath{\Lambda}$ invariant-mass plots. Production and decay systematics of the $H$ are discussed.