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

Franconi, L.; Miucci, A.; Merlassino, C.; Haug, S.; Weber, M. S.; Anders, J. K.; Beck, H. P.; Ereditato, A. (2019). Measurement of angular and momentum distributions of charged particles within and around jets in Pb+Pb and pp collisions at \sqrts\mathrmNN = 5.02 TeV with the ATLAS detector. Physical review. C - nuclear physics, 100(6) American Institute of Physics 10.1103/PhysRevC.100.064901

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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.

#### Item Type:

Journal Article (Original Article)

#### Division/Institute:

08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

#### UniBE Contributor:

Franconi, Laura; Miucci, Antonio; Merlassino, Claudia; Haug, Sigve; Weber, Michael; Anders, John Kenneth; Beck, Hans Peter and Ereditato, Antonio

#### Subjects:

500 Science > 530 Physics

0556-2813

#### Publisher:

American Institute of Physics

English

#### Submitter:

BORIS Import LHEP

#### Date Deposited:

01 May 2020 14:17

29 May 2020 09:36

#### Publisher DOI:

10.1103/PhysRevC.100.064901

Es sind nur die Berner Autoren namentlich erwaehnt

#### BORIS DOI:

10.7892/boris.143557

#### URI:

https://boris.unibe.ch/id/eprint/143557