Most Strange Dibaryon from Lattice QCD

The Omega Omega system in the S-1(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) similar or equal to 146 MeV at a lattice spacing of a similar or equal to 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)) fm, the effective range r(eff) = 1.27(3)((+0.06)(-0.03)) fm, and the binding energy B-Omega Omega = 1.6(6)((+0.7)(-0.6)) 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.