The proton-$\Omega$ correlation function in Au + Au collisions at $\sqrt{s_{NN}}$ =200GeV

Abstract

We present the first measurement of the proton-$\Omega$ correlation function in heavy-ion collisions for central (0-40%) and peripheral (40-80%) Au+Au collisions at $\sqrt{s_{NN}}$ =200 GeV by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). Predictions for the ratio of peripheral collisions to central collisions for the proton-$\Omega$ correlation function are sensitive to the presence of a nucleon-$\Omega$ bound state. These predictions are based on the proton-$\Omega$ interaction extracted from (2+1)-flavor lattice QCD calculations at the physical point. The measured ratio of proton-$\Omega$ correlation function from peripheral (small system) to central (large system) collisions is less than unity for relative momentum smaller than 40 MeV/$c$. Comparison of our measured correlation ratio with the theoretical calculation slightly favors a proton-$\Omega$ bound system with a binding energy of ∼ 27 MeV.