This letter presents a measurement of the nuclear modification factor of large-radius jets in sqrt[s_{NN}]=5.02  TeV Pb+Pb collisions by the ATLAS experiment. The measurement is performed using 1.72  nb^{-1} and 257  pb^{-1} of Pb+Pb and pp data, respectively. The large-radius jets are reconstructed with the anti-k_{t} algorithm using a radius parameter of R=1.0, by reclustering anti-k_{t} R=0.2 jets, and are measured over the transverse momentum (p_{T}) kinematic range of 158<1000  GeV and absolute pseudorapidity |y|<2.0. The large-radius jet constituents are further reclustered using the k_{t} algorithm in order to obtain the splitting parameters, sqrt[d_{12}] and ΔR_{12}, which characterize the transverse momentum scale and angular separation for the hardest splitting in the jet, respectively. The nuclear modification factor, R_{AA}, obtained by comparing the Pb+Pb jet yields to those in pp collisions, is measured as a function of jet transverse momentum (p_{T}) and sqrt[d_{12}] or ΔR_{12}. A significant difference in the quenching of large-radius jets having single subjet and those with more complex substructure is observed. Systematic comparison of jet suppression in terms of R_{AA} for different jet definitions is also provided. Presented results support the hypothesis that jets with hard internal splittings lose more energy through quenching and provide a new perspective for understanding the role of jet structure in jet suppression.

Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at √ˢNN=5.02  TeV with the ATLAS Detector [Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at sqrt[s_{NN}]=5.02  TeV with the ATLAS Detector] / G. Aad, B.A.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 131:17(2023 Oct 23), pp. 172301.1-172301.22. [10.1103/PhysRevLett.131.172301]

Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at √ˢNN=5.02  TeV with the ATLAS Detector [Measurement of Suppression of Large-Radius Jets and Its Dependence on Substructure in Pb+Pb Collisions at sqrt[s_{NN}]=5.02  TeV with the ATLAS Detector]

A. Andreazza;E. Ballabene;A. Carbone;L. Carminati;S. D'Auria;L. Dell'Asta;M. Fanti;M. Lazzaroni;C. Meroni;A. Murrone;L. Perini;F. Piazza;F. Ragusa;A. Stabile;
2023

Abstract

This letter presents a measurement of the nuclear modification factor of large-radius jets in sqrt[s_{NN}]=5.02  TeV Pb+Pb collisions by the ATLAS experiment. The measurement is performed using 1.72  nb^{-1} and 257  pb^{-1} of Pb+Pb and pp data, respectively. The large-radius jets are reconstructed with the anti-k_{t} algorithm using a radius parameter of R=1.0, by reclustering anti-k_{t} R=0.2 jets, and are measured over the transverse momentum (p_{T}) kinematic range of 158<1000  GeV and absolute pseudorapidity |y|<2.0. The large-radius jet constituents are further reclustered using the k_{t} algorithm in order to obtain the splitting parameters, sqrt[d_{12}] and ΔR_{12}, which characterize the transverse momentum scale and angular separation for the hardest splitting in the jet, respectively. The nuclear modification factor, R_{AA}, obtained by comparing the Pb+Pb jet yields to those in pp collisions, is measured as a function of jet transverse momentum (p_{T}) and sqrt[d_{12}] or ΔR_{12}. A significant difference in the quenching of large-radius jets having single subjet and those with more complex substructure is observed. Systematic comparison of jet suppression in terms of R_{AA} for different jet definitions is also provided. Presented results support the hypothesis that jets with hard internal splittings lose more energy through quenching and provide a new perspective for understanding the role of jet structure in jet suppression.
Settore FIS/01 - Fisica Sperimentale
Settore ING-INF/07 - Misure Elettriche e Elettroniche
23-ott-2023
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.172301
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1021337
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