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Measurement of angular and momentum distributions of charged particles within and around jets in Pb+Pb and pp collisions at sNN =5.02 TeV with the ATLAS detector

  • Author(s): Aad, G
  • Abbott, B
  • Abbott, DC
  • Abed Abud, A
  • Abeling, K
  • Abhayasinghe, DK
  • Abidi, SH
  • Abouzeid, OS
  • Abraham, NL
  • Abramowicz, H
  • Abreu, H
  • Abulaiti, Y
  • Acharya, BS
  • Achkar, B
  • Adachi, S
  • Adam, L
  • Adam Bourdarios, C
  • Adamczyk, L
  • Adamek, L
  • Adelman, J
  • Adersberger, M
  • Adiguzel, A
  • Adorni, S
  • Adye, T
  • Affolder, AA
  • Afik, Y
  • Agapopoulou, C
  • Agaras, MN
  • Aggarwal, A
  • Agheorghiesei, C
  • Aguilar-Saavedra, JA
  • Ahmadov, F
  • Ahmed, WS
  • Ai, X
  • Aielli, G
  • Akatsuka, S
  • Åkesson, TPA
  • Akilli, E
  • Akimov, AV
  • Al Khoury, K
  • Alberghi, GL
  • Albert, J
  • Alconada Verzini, MJ
  • Alderweireldt, S
  • Aleksa, M
  • Aleksandrov, IN
  • Alexa, C
  • Alexandre, D
  • Alexopoulos, T
  • Alfonsi, A
  • Alfonsi, F
  • Alhroob, M
  • Ali, B
  • Alimonti, G
  • Alison, J
  • Alkire, SP
  • Allaire, C
  • Allbrooke, BMM
  • Allen, BW
  • Allport, PP
  • Aloisio, A
  • Alonso, A
  • Alonso, F
  • Alpigiani, C
  • Alshehri, AA
  • Alvarez Estevez, M
  • Álvarez Piqueras, D
  • Alviggi, MG
  • Amaral Coutinho, Y
  • Ambler, A
  • Ambroz, L
  • Amelung, C
  • Amidei, D
  • Amor Dos Santos, SP
  • Amoroso, S
  • Amrouche, CS
  • An, F
  • Anastopoulos, C
  • Andari, N
  • Andeen, T
  • Anders, CF
  • Anders, JK
  • Andreazza, A
  • Andrei, V
  • Anelli, CR
  • Angelidakis, S
  • Angerami, A
  • Anisenkov, AV
  • Annovi, A
  • Antel, C
  • Anthony, MT
  • Antonelli, M
  • Antrim, DJA
  • Anulli, F
  • Aoki, M
  • Aparisi Pozo, JA
  • Aperio Bella, L
  • Arabidze, G
  • Araque, JP
  • Araujo Ferraz, V
  • et al.
Abstract

© 2019 CERN. Studies of the fragmentation of jets into charged particles in heavy-ion collisions can provide information about the mechanism of jet quenching by the hot and dense QCD matter created in such collisions, the quark-gluon plasma. This paper presents a measurement of the angular distribution of charged particles around the jet axis in sNN=5.02 TeV Pb+Pb and pp collisions, using the ATLAS detector at the LHC. The Pb+Pb and pp data sets have integrated luminosities of 0.49nb-1 and 25pb-1, respectively. The measurement is performed for jets reconstructed with the anti-kt algorithm with radius parameter R=0.4 and is extended to an angular distance of r=0.8 from the jet axis. Results are presented as a function of Pb+Pb collision centrality and distance from the jet axis for charged particles with transverse momenta in the 1- to 63-GeV range, matched to jets with transverse momenta in the 126- to 316-GeV range and an absolute value of jet rapidity of less than 1.7. Modifications to the measured distributions are quantified by taking a ratio to the measurements in pp collisions. Yields of charged particles with transverse momenta below 4 GeV are observed to be increasingly enhanced as a function of angular distance from the jet axis, reaching a maximum at r=0.6. Charged particles with transverse momenta above 4 GeV have an enhanced yield in Pb+Pb collisions in the jet core for angular distances up to r=0.05 from the jet axis, with a suppression at larger distances.

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