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 (𝑅AA). The jet 𝑅AA is measured as a function of jet 𝑝T, the charged 𝑘𝑡 splitting scale (√ 𝑑12), and the angular separation (Δ𝑅12) of two leading sub-jets. The jet 𝑅AA gradually decreases with increasing √ 𝑑12, implying significantly stronger suppression of large-radius jets with larger 𝑘𝑡 splitting scale. The jet 𝑅AA gradually decreases for Δ𝑅12 in the range 0.01−0.2 and then remains consistent with a constant for Δ𝑅12 ≳ 0.2. The observed significant dependence of jet suppression on the jet substructure will provide new insights into its role in the quenching process.

Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2025). Measurement of substructure-dependent suppression of large-radius jets with charged particles in Pb+Pb collisions with ATLAS. PHYSICS LETTERS. SECTION B, 871, 1-17 [10.1016/j.physletb.2025.139929].

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

Alberghi, G. L.;Alfonsi, F.;Ballabene, E.;Bellagamba, L.;Bianco, G.;Boscherini, D.;Bruni, A.;Carbone, A.;Carratta, G.;Corchia, F. A.;Cremonini, D.;De Castro, S.;Fabbri, F.;Fabbri, L.;Franchini, M.;Gabrielli, A.;Giacobbe, B.;Lasagni Manghi, F.;Levrini, G.;Nechaeva, S.;Polini, A.;Rinaldi, L.;Romano, M.;Sanzani, E.;Sbarra, C.;Sbrizzi, A.;Semprini-Cesari, N.;Sioli, M.;Todome, K.;Valentinetti, S.;Villa, M.;Vittori, C.;Vivarelli, I.;Zoccoli, A.;
2025

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 (𝑅AA). The jet 𝑅AA is measured as a function of jet 𝑝T, the charged 𝑘𝑡 splitting scale (√ 𝑑12), and the angular separation (Δ𝑅12) of two leading sub-jets. The jet 𝑅AA gradually decreases with increasing √ 𝑑12, implying significantly stronger suppression of large-radius jets with larger 𝑘𝑡 splitting scale. The jet 𝑅AA gradually decreases for Δ𝑅12 in the range 0.01−0.2 and then remains consistent with a constant for Δ𝑅12 ≳ 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
Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2025). Measurement of substructure-dependent suppression of large-radius jets with charged particles in Pb+Pb collisions with ATLAS. PHYSICS LETTERS. SECTION B, 871, 1-17 [10.1016/j.physletb.2025.139929].
Aad, G.; Aakvaag, E.; Abbott, B.; Abdelhameed, S.; Abeling, K.; Abicht, N. J.; Abidi, S. H.; Aboelela, M.; Aboulhorma, A.; Abramowicz, H.; Abulaiti, Y...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1047877
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