2021/10/25 by Jasmine Brewer, Quinn Brodsky, Krishna Rajagopal · 35 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Jet (fluid) #Jet quenching #Mechanics #Nuclear physics #Observable #Particle physics #Particle physics theoretical and experimental studies #Physics #Plasma #Quantum Chromodynamics and Particle Interactions #Quark–gluon plasma #Quenching (fluorescence) #Substructure #hep-ph #nucl-th
paper · pdf · open access · doi:10.1007/jhep02(2022)175
published in Journal of High Energy Physics 2022(2) (Springer Nature) · 16 pages, 8 figures
arxiv created 2021/10/25 · openalex publication_date 2022/02/01 · arxiv updated 2022/03/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the impact of selection biases on jet structure and substructure observables and separate these effects from effects caused by jet quenching. We use the angular separation ΔR of the hardest splitting in a jet as the primary example observable. We first conduct a simplified Monte Carlo study in which it is possible to identify the same jet after quenching in a heavy ion collision and as it would have been if it had formed in vacuum. We select a sample of jets by placing a cut on their quenched pT and, as is possible only in a Monte Carlo study, compare to the same jets unquenched, and see that the ΔR distribution seems to be unmodified. However, if we select a sample of jets formed in vacuum by placing a cut on their unquenched pT and compare to those same jets after quenching, we see a significant enhancement in the number of jets with large ΔR, primarily due to the soft particles in the jet that originate from the wake in the droplet of quark-gluon plasma excited by the parton shower. We confirm that the jets contributing to this enhancement are those jets which lost the most energy, which were not included in the sample selected after quenching; jets selected after quenching are those which lose a small fraction of their energy. Next, we employ a method that is available to experimentalists: in a sample of jets with a recoiling Z boson, we show that selecting jets based on the jet pT after quenching yields a ΔR distribution that appears unmodified while selecting a sample of jets produced in association with a Z boson whose (unmodified) pT is above some cut yields a significant enhancement in the number of jets with large ΔR. We again confirm that this is due to particles from the wake, and that the jets contributing to this enhancement are those which have lost a significant fraction of their energy.