Speaker: Virginia Bailey

Host: Marzia Rosati

Title: Studying nuclear matter in extreme conditions using jets

Abstract: Less than a second after the Big Bang, the universe was made of a hot and dense soup of nuclear matter, called the quark-gluon plasma (QGP). The study of this state of matter, which can be reproduced in high energy collisions of heavy nuclei, gives insight into the formation of the early universe and the intrinsic properties of nuclear matter in extreme conditions. The QGP has been shown to "flow", behaving as a liquid with an extremely low viscosity, however the microscopic nature of the QGP which leads to this behavior remains an open question. High energy quarks and gluons produced in the same QGP producing collisions provide an excellent probe of the small scale structure of the medium. These partons pass through the medium and interact, losing energy, before fragmenting into a spray of particles called a jet.

sPHENIX is a state-of-the-art detector built at the Relativistic Heavy Ion Collider (RHIC) with the explicit goal of measuring jets and other high energy probes of the QGP. One key component of the sPHENIX detector is its hadronic calorimeter system, which allows for full electromagnetic and hadronic jet energy measurements for the first time at RHIC. sPHENIX began commissioning in 2023 and has collected high statistics Au+Au, p+p, and O+O collision datasets. In this talk I will discuss the sPHENIX detector with a particular emphasis on the calorimeter system, baseline measurements of jets in p+p collisions, and present the first jet quenching results from sPHENIX. Furthermore, I will discuss the upcoming electron-ion collider which aims to make precision measurements of nuclei and will provide important baseline information for understanding measurements of the QGP. 

Bio: Virginia Bailey is an NSF postdoctoral fellow at Georgia State University who focuses on the study of nuclear physics in extreme conditions. She received her PhD from the University of Illinois Urbana-Champaign, where she was a member of the ATLAS collaboration at the Large Hadron Collider. Her thesis focused on the measurement of path-length dependent energy loss of jets in heavy-ion collisions. In 2022, Dr. Bailey joined Georgia State University as a postdoctoral researcher stationed at Brookhaven National Lab working on the sPHENIX experiment at the Relativistic Heavy Ion Collider. She has served as a calorimeter detector expert during all three years of commissioning and data-taking. Since 2024 she has served as co-convener of the sPHENIX jet structure topical group, overseeing the first results from the sPHENIX jet physics program, and co-led the first jet quenching measurement in sPHENIX. She is also a member of the ePIC collaboration, the first detector to be built for the future Electron Ion Collider, with a focus on the barrel hadronic calorimeter.