Next generation jet measurements with sPHENIX
2019 January 11
The proposed sPHENIX detector at the Relativistic Heavy Ion Collider (RHIC), designed to take advantage of technological advances from the Large Hadron Collider (LHC), will allow measurements of jets and jet correlations with a kinematic reach that will overlap with measurements made at the LHC. This is made possible by taking advantage of the increased luminosity due to accelerator upgrades and the ability of sPHENIX to sample the entire luminosity. Particle jets, formed when a hard scattered parton fragments and then hadronizes into a spray of particles, are an excellent as a probe of the Quark Gluon Plasma (QGP) formed in heavy-ion collisions. As these partons traverse the QGP formed in heavy ion collisions, they lose energy to the medium, in a process called jet quenching. The physics of this process can be explored by comparing jet- based observables in heavy-ion collisions to those in proton-proton collisions. This is necessary in order to answer the fundamental questions of how and why partons lose energy in the QGP, which will require that we characterize both the medium induced modification of the jet fragmentation pattern, and the correlation of the lost energy with the jet axis. Observables which use the correlation between a high energy photon and a jet are especially useful as the photon kinematics are more closely correlated with the parton kinematics, as well as preferentially selecting quark jets over gluon jets. In addition to inclusive or semi-inclusive jet observables, advances in both theory and measurement at the LHC have provided a suite of new observables which are related to the fragmentation pattern of the jet and how it is modified in the QGP medium. These observables require the precise tracking and calorimetry that the sPHENIX design has. We will show the performance of jet and gamma-jet observables within the sPHENIX detector, including the jet energy scale and resolution in both proton-proton and heavy-ion collisions. These results are simulated with the improved framework developed for understanding the performance of the new detector for measuring jets and photons in a heavy ion environment.