sPHENIX Study of Jet Substructure as a Tool for Understanding QGP Modifications

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab houses the new sPHENIX experiment, designed to measure Quark-Gluon Plasma (QGP) properties using a diverse set of high-energy hard probes. One primary physics goal of sPHENIX is to study the nuclear modification of jets due to the QGP. The sPHENIX detector consists of a multitude of different sub-detectors, and due to its increased granularity in calorimetry, along with tracking, sPHENIX’s jet reconstruction can offer a more precise vision of what occurs during parton showering and how the internal mechanism of jets is modified by the QGP medium.

Jet substructure observables, such as the opening angle θ_SJ, can offer interesting connections between jet opening angle and jet quenching. This new approach to probing parton energy loss can provide insight into measuring the QGP’s color coherence length, λ_⊥, the characteristic distance over which the QGP can resolve color charge separation between two partons. sPHENIX data are expected to improve on the precision of previous measurements of the coherence length at RHIC. This work presents preliminary progress toward such a measurement using sPHENIX Run-24 200 GeV p+p collision data. The dataset corresponds to an integrated luminosity of 13.3 pb^-1, collected with a fully triggered system with a |z_vertex| < 10 cm. We focus on early steps toward substructure extraction at the calorimeter level using Monte Carlo comparisons.