# Probing QCD critical fluctuations from intermittency analysis in relativistic heavy-ion collisions

## TL;DR

This paper demonstrates that intermittency analysis in relativistic heavy-ion collisions can serve as an effective probe for detecting QCD critical fluctuations, revealing non-monotonic energy dependence linked to critical phenomena.

## Contribution

It establishes a theoretical relation between intermittency index and baryon density fluctuations and applies it to experimental data, highlighting its potential for QCD critical point detection.

## Key findings

- Intermittency correlates with critical density fluctuations in 3D Ising universality class.
- Experimental data shows a peak in intermittency index around 20-27 GeV collision energy.
- Transport model without critical physics fails to reproduce observed intermittency behavior.

## Abstract

It is shown that intermittency, a self-similar correlation with respect to the size of the phase space volume, is sensitive to critical density fluctuations of baryon numbers in a system belonging to the three-dimensional (3D) Ising universality class. The relation between intermittency index and relative baryon density fluctuation is obtained. We thus suggest that measuring the intermittency in relativistic heavy-ion collisions could be used as a good probe of density fluctuations associated with the QCD critical phenomena. From recent preliminary results on neutron density fluctuations in central Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV at RHIC/STAR, the collision energy dependence of intermittency index is extracted and shows a non-monotonic behavior with a peak at around 20 - 27 GeV, indicating that the strength of intermittency becomes the largest in this energy region. The transport UrQMD model without implementing critical physics cannot describe the observed behavior.