Measurements of jet substructure in Pb+Pb collisions provide key insights into the mechanism of jet quenching in the hot and dense QCD medium created in these collisions.This Letter presents a measurement of the suppression of large-radius jets with a radius parameter of R=1.0 and its dependence on the jet substructure. The measurement uses 1.72 nb-1 of Pb+Pb data and 255 pb-1 of pp data, both at sNN=5.02 TeV, recorded with the ATLAS detector at the Large Hadron Collider. Large-radius jets are reconstructed by reclustering R=0.2 calorimetric jets and are measured for transverse momentum above 200 GeV. Jet substructure is evaluated using charged-particle tracks, and the overall level of jet suppression is quantified using the jet nuclear modification factor ( R AA). The jet R AA is measured as a function of jet p T, the charged kt splitting scale (d12), and the angular separation (? R 12) of two leading sub-jets. The jet R AA gradually decreases with increasing d12, implying significantly stronger suppression of large-radius jets with larger kt splitting scale. The jet R AA gradually decreases for ? R 12 in the range 0.01-0.2 and then remains consistent with a constant for ? R 12 ? 0.2. The observed significant dependence of jet suppression on the jet substructure will provide new insights into its role in the quenching process.

Measurement of substructure-dependent suppression of large-radius jets with charged particles in Pb+Pb collisions with ATLAS

Capua, M.;Mastroberardino, A.;Meoni, E.;Schioppa, M.;Tassi, E.;
2025-01-01

Abstract

Measurements of jet substructure in Pb+Pb collisions provide key insights into the mechanism of jet quenching in the hot and dense QCD medium created in these collisions.This Letter presents a measurement of the suppression of large-radius jets with a radius parameter of R=1.0 and its dependence on the jet substructure. The measurement uses 1.72 nb-1 of Pb+Pb data and 255 pb-1 of pp data, both at sNN=5.02 TeV, recorded with the ATLAS detector at the Large Hadron Collider. Large-radius jets are reconstructed by reclustering R=0.2 calorimetric jets and are measured for transverse momentum above 200 GeV. Jet substructure is evaluated using charged-particle tracks, and the overall level of jet suppression is quantified using the jet nuclear modification factor ( R AA). The jet R AA is measured as a function of jet p T, the charged kt splitting scale (d12), and the angular separation (? R 12) of two leading sub-jets. The jet R AA gradually decreases with increasing d12, implying significantly stronger suppression of large-radius jets with larger kt splitting scale. The jet R AA gradually decreases for ? R 12 in the range 0.01-0.2 and then remains consistent with a constant for ? R 12 ? 0.2. The observed significant dependence of jet suppression on the jet substructure will provide new insights into its role in the quenching process.
2025
Jet quenching
Jets & heavy flavor physics
Quark-gluon plasma
Relativistic heavy-ion collisions
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/400092
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