Nucleon clustering at freezeout, far from and close to the QCD critical point

by Shuryak Edward

Tuesday Nov 10, 2020, 11:00 AM → 12:00 PM US/Eastern

Clustering of nucleons at freezeout has been studied by a number of theoretical tools, including semiclassical (fluctons), hyperharmonics and, lately, direct Path Intergal Monte Carlo. It was found to be effective starting from four nucleons, with ``preclusters" feeding into multiple bound states decaying into channels with light nuclei $d,t,He^3$ and affecting proton distribution (kurtosis).   It was further found that even a minor increase of the range of nuclear forces  increases clustering dramatically. Furthermore, if there exists the QCD critical point (CP) with large correlation length $\xi$, attraction due to binary forces becomes unrealistically  large. The resolution of this paradox was found to be
due to repulsive many-body forces near CP,  overcoming the binary attraction and effectively suppressing clustering. We briefly discuss current experimental data and point out locations hinting at certain drop in clustering.

edwardshuryak.mp4

manybody_clusters_BNL.pdf