The heavy ions are "preheated" prior to hight energy collisions

Abstract

The so called "isobar run" or RHIC was designed to compare a number of observables for collisions of 96 40 Zr with those of 96 44 Ru, aimed at identification of Z-dependent effects. However, the STAR data have shown, with unprecedented accuracy, that these two nuclides have properties which differ stronger than expected, and multiple studies tried to quantify their shape differences, in relation to various observables. General consensus is that it somehow should be related to nuclear structure calculations, for the ground and lowest excited states. Yet the precise connection between these fields -low and high energy nuclear physics -is still missing. In this paper I propose such a connection, via a concept of thermal density matrices of a "preheated" nuclei.

Search for the chiral magnetic effect in collisions between two isobars with nuclear structures

“…In other words, their nucleon density distributions should be described by a deformed Woods-Saxon (WS) form with some proper deformation parameters considering these effects. It has been proposed that the isobar collision experiment provides a new experimental way to study nuclear deformation and nuclear structure [40,41]. In this work, we first try to find the best setting of WS parameters which can reproduce the STAR isobar data, then constraint the strength of possible CME signal in Ru + Ru and Zr + Zr collisions at √ s =200 GeV by using a multiphase transport (AMPT) model including both the signal of chiral magnetic effect and the good setting of WS parameters.…”

An overview of new measurements of flow, chirality, and vorticity from STAR experiment

“…isobar baseline and background estimations. Theoretical model calculations[78][79][80][81][82][83][84][85][86][87][88][89][90] are necessary to understand above physics. Unlike RIBLL, FRIB and NICA at low and medium energies, isobar collisions open up new opportunity to study nuclear structure at a very short time scale (∼ 10 −23 s) through heavy-ion collisions.• One fundamental property of light atomic nuclei in unusual nuclear structure…”