Little-Bang and Femto-Nova in Nucleus-Nucleus Collisions

TL;DR

This paper reviews the current experimental and theoretical understanding of hot and dense QCD matter in nucleus-nucleus collisions, highlighting the search for the QCD Critical Point, particle production, and the phenomena of Little-Bang and Femto-Nova.

Contribution

It provides a comprehensive summary of recent experimental data, theoretical models, and future prospects in the study of baryon-rich matter and QCD phase transitions in nuclear collisions.

Findings

Transition from grand canonical to canonical ensemble at low energies

Evidence supporting the creation of quark-gluon plasma at high temperatures

Potential observation of vorticity and magnetic fields in non-central collisions

Abstract

We make a theoretical and experimental summary of the state-of-the-art status of hot and dense QCD matter studies on selected topics. We review the Beam Energy Scan program for the QCD phase diagram and present the current status of search for QCD Critical Point, particle production in high baryon density region, hypernuclei production, and global polarization effects in nucleus-nucleus collisions. The available experimental data in the strangeness sector suggests that a grand canonical approach in thermal model at high collision energy makes a transition to the canonical ensemble behavior at low energy. We further discuss future prospects of nuclear collisions to probe properties of baryon-rich matter. Creation of a quark-gluon plasma at high temperature and low baryon density has been called the "Little-Bang" and, analogously, a femtometer-scale explosion of baryon-rich matter at lower collision energy could be called the "Femto-Nova", which may possibly sustain substantial vorticity and magnetic field for non-head-on collisions.