In Ultra-Relativistic Heavy Ion collisions, such as those done at the Large Hadron Collider (LHC) and Relativistic Heavy Ion Collider (RHIC), the high energy densities create an exotic state of matter not seen since the first 10-4 seconds past the Big Bang, a Quark Gluon Plasma (QGP) where quarks and gluons are not confined into hadronic bound states.
The properties and evolution of this matter can be studied using a naturally existing probe: the hard QCD (Quantum Chromo-Dynamics) jets that are produced in partonic hard scatters at the beginning of the collisions. Similarly to the x-rays in medical Computed Tomography, the escaping jets reflect the transverse structure of the medium. However, this analogy breaks down in two key ways. The QGP, unlike the human body, is rapidly evolving on the same timescale of the jet’s passing through of the medium. Additionally, the interaction of the jet with the QGP is not fully understood and may modify the structure of jets beyond a simple attenuation. The field of studying these jet-medium interactions, called jet tomography, is advanced by the research in this thesis using correlations high momentum p0 mesons and hadrons arising from the same jet-producing hard scatter process. The focus in this study is on experimentally varying the path-length traversed by the involved jets by examining the correlations with respect to the reaction plane of the colliding ions. This is done using Pb-Pb collisions measured by ALICE detector at the LHC at √SNN = 5.02TeV.
Thesis advisor: John Harris (john.harris@yale.edu)