# Measuring jet energy loss fluctuations in the quark-gluon plasma via multiparticle correlations

**Authors:** Abraham Holtermann, Jacquelyn Noronha-Hostler, Anne M. Sickles, Xiaoning Wang  
**arXiv:** [2402.03512](https://arxiv.org/abs/2402.03512)  
**Date:** 2024-02-05  
**Summary page:** https://www.summarizepaper.com/en/paper/2402.03512v1/

## Key points

- Quark-gluon plasma (QGP) is a high-temperature state of matter formed in collisions of nuclei at relativistic energies
- Jets with high transverse momentum ($p_T$) are used to study properties of QGP, originating from quarks and gluons undergoing large momentum transfers
- Fourier harmonics $v_n(p_T)$ provide insight into path length dependence of jet energy loss within QGP
- Framework introduced in the paper focuses on characterizing fluctuations in jet energy loss using multivariate moments and cumulants as new experimental observables
- Event-by-event fluctuations in azimuthal anisotropies can quantify magnitude and variations in jet energy loss
- Abundance of data from recent and ongoing runs at LHC, sPHENIX, and STAR experiments allows for precise jet measurements and estimation of fluctuations in jet energy loss within QGP medium
- Study can be extended to investigate fluctuations in rare probe production and interactions with QGP using similar approaches and observables

## Summary

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The quark-gluon plasma (QGP) is a high-temperature state of matter formed in the collisions of two nuclei at relativistic energies. Jets with high transverse momentum ($p_T$) are utilized as probes to study the properties of this unique form of matter, originating from quarks and gluons that undergo large momentum transfers in the initial stages of the collisions. The Fourier harmonics for anisotropies in the high $p_T$ particle yield, denoted as $v_n(p_T)$, provide insight into the path length dependence of jet energy loss within the QGP. This paper introduces a framework that builds upon existing measurements of jet energy loss using $v_n(p_T)$ by focusing on characterizing fluctuations in jet energy loss. These fluctuations have not yet been experimentally constrained and can be measured by employing a set of multivariate moments and cumulants as new experimental observables. By comparing event-by-event fluctuations in the azimuthal anisotropies of rare probes to those of soft particles, both the magnitude and variations in event-by-event jet energy loss can be quantified. With recent and ongoing high luminosity runs at the LHC, alongside upcoming data from sPHENIX and STAR experiments at RHIC, there will be an abundance of data available for precise jet measurements. This wealth of data presents an opportunity to apply the observables and analysis methods discussed in this paper to isolate estimates for fluctuations in jet energy loss within the QGP medium. Furthermore, while this study has primarily focused on jet probes-of-interest (POIs), it is noted that these approaches and observables can also be applied to other types of POIs to investigate fluctuations in rare probe production and interactions with the QGP. In conclusion, measuring jet energy loss fluctuations in the quark-gluon plasma via multiparticle correlations represents a significant advancement in our understanding of this exotic state of matter. The utilization of innovative observables and analysis techniques presented in this paper holds promise for further elucidating the complex dynamics occurring within the QGP during high-energy nuclear collisions.