AI Article Synopsis
- This article discusses the analysis of groomed jet substructure in proton-proton (pp) and lead-lead (Pb-Pb) collisions using the ALICE detector at a collision energy of 5.02 TeV.
- The study employs a soft drop grooming algorithm to isolate hard parton splittings and measures the groomed jet momentum splitting fraction and radius, revealing distinct behavior in jet structure under different collision conditions.
- Notably, a narrowing of the groomed jet radius distribution in Pb-Pb collisions suggests changes in jet angular structure due to quark-gluon plasma, while no significant differences are observed in momentum splitting fractions, contributing valuable insights into jet energy-loss mechanisms.
Article Abstract
This article presents groomed jet substructure measurements in pp and Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV with the ALICE detector. The soft drop grooming algorithm provides access to the hard parton splittings inside a jet by removing soft wide-angle radiation. We report the groomed jet momentum splitting fraction, z_{g}, and the (scaled) groomed jet radius, θ_{g}. Charged-particle jets are reconstructed at midrapidity using the anti-k_{T} algorithm with resolution parameters R=0.2 and R=0.4. In heavy-ion collisions, the large underlying event poses a challenge for the reconstruction of groomed jet observables, since fluctuations in the background can cause groomed parton splittings to be misidentified. By using strong grooming conditions to reduce this background, we report these observables fully corrected for detector effects and background fluctuations for the first time. A narrowing of the θ_{g} distribution in Pb-Pb collisions compared to pp collisions is seen, which provides direct evidence of the modification of the angular structure of jets in the quark-gluon plasma. No significant modification of the z_{g} distribution in Pb-Pb collisions compared to pp collisions is observed. These results are compared with a variety of theoretical models of jet quenching, and provide constraints on jet energy-loss mechanisms and coherence effects in the quark-gluon plasma.
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| http://dx.doi.org/10.1103/PhysRevLett.128.102001 | DOI Listing |
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- This article discusses the analysis of groomed jet substructure in proton-proton (pp) and lead-lead (Pb-Pb) collisions using the ALICE detector at a collision energy of 5.02 TeV.
- The study employs a soft drop grooming algorithm to isolate hard parton splittings and measures the groomed jet momentum splitting fraction and radius, revealing distinct behavior in jet structure under different collision conditions.
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