Hyperon spin correlation in high-energy heavy-ion collisions

Abstract

Recent experimental data show an unexpectedly large spin alignment of $\ddot{I}•$ mesons in high-energy heavy-ion collisions, which can be explained by short-distance fluctuations of strong-force fields (vector $\ddot{I}•$ fields) within the constituent-quark model. We calculate the hyperon spin correlations within the same model, taking into account hydrodynamic effects and a $\ddot{I}•$ field fluctuating in space-time according to a Gaussian distribution. The $\hat{I}›\bar{\hat{I}}›$ spin correlation induced by the $\ddot{I}•$ field is shown to be negative as opposed to that of $\hat{I}›\hat{I}›$ or $\bar{\hat{I}}›\bar{\hat{I}}›$. We thus propose a new net spin-correlation observable as a sensitive probe to separate strong-force effects from hydrodynamic ones. With the strength of the field fluctuations extracted from the observed $\ddot{I}•$ spin alignment, we predict the collision-energy dependence of the hyperon spin correlations and also investigate the dependence of the net spin correlation on azimuthal-angle and rapidity difference.

Main text: 6 pages, 4 figures. Supplemental Material: 3 pages, 3 figures