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Title: Observation of medium induced modifications of jet fragmentation in PbPb collisions using isolated-photon-tagged jets

Abstract

Measurements of fragmentation functions for jets associated with an isolated photon are presented for the first time in pp and PbPb collisions. The analysis uses data collected with the CMS detector at the CERN LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Fragmentation functions are obtained for jets with p$$_\mathrm{T}^\text{jet} >$$ 30 GeV in events containing an isolated photon with p$$_\mathrm{T}^\gamma>$$ 60 GeV, using charged tracks with transverse momentum p$$_\mathrm{T}^\text{trk} >$$ 1 GeV in a cone around the jet axis. The association with an isolated photon constrains the initial p$$_\mathrm{T}$$ and azimuthal angle of the parton whose shower produced the jet. For central PbPb collisions, modifications of the jet fragmentation functions are observed when compared to those measured in pp collisions, while no significant differences are found in the 50% most peripheral collisions. Jets in central PbPb events show an excess (depletion) of low (high) p$$_\mathrm{T}$$ particles, with a transition around 3 GeV.

Authors:
;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
CMS
OSTI Identifier:
1420421
Report Number(s):
FERMILAB-PUB-18-040-CMS; CMS-HIN-16-014; CERN-EP-2017-337; arXiv:1801.04895
1648162
DOE Contract Number:
AC02-07CH11359
Resource Type:
Journal Article
Resource Relation:
Journal Name: TBD
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Sirunyan, Albert M, and et al. Observation of medium induced modifications of jet fragmentation in PbPb collisions using isolated-photon-tagged jets. United States: N. p., 2018. Web.
Sirunyan, Albert M, & et al. Observation of medium induced modifications of jet fragmentation in PbPb collisions using isolated-photon-tagged jets. United States.
Sirunyan, Albert M, and et al. Mon . "Observation of medium induced modifications of jet fragmentation in PbPb collisions using isolated-photon-tagged jets". United States. doi:. https://www.osti.gov/servlets/purl/1420421.
@article{osti_1420421,
title = {Observation of medium induced modifications of jet fragmentation in PbPb collisions using isolated-photon-tagged jets},
author = {Sirunyan, Albert M and et al.},
abstractNote = {Measurements of fragmentation functions for jets associated with an isolated photon are presented for the first time in pp and PbPb collisions. The analysis uses data collected with the CMS detector at the CERN LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Fragmentation functions are obtained for jets with p$_\mathrm{T}^\text{jet} >$ 30 GeV in events containing an isolated photon with p$_\mathrm{T}^\gamma>$ 60 GeV, using charged tracks with transverse momentum p$_\mathrm{T}^\text{trk} >$ 1 GeV in a cone around the jet axis. The association with an isolated photon constrains the initial p$_\mathrm{T}$ and azimuthal angle of the parton whose shower produced the jet. For central PbPb collisions, modifications of the jet fragmentation functions are observed when compared to those measured in pp collisions, while no significant differences are found in the 50% most peripheral collisions. Jets in central PbPb events show an excess (depletion) of low (high) p$_\mathrm{T}$ particles, with a transition around 3 GeV.},
doi = {},
journal = {TBD},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2018},
month = {Mon Jan 15 00:00:00 EST 2018}
}