Observation of Medium-Induced Modifications of Jet Fragmentation in Pb-Pb Collisions at ?sNN=5.02??TeV Using Isolated Photon-Tagged Jets
Yükleniyor...
Tarih
2018
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
American Physical Society
Erişim Hakkı
Özet
Measurements of fragmentation functions for jets associated with an isolated photon are presented for the first time in pp and Pb-Pb 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 pjetT>30??GeV/c in events containing an isolated photon with p?T>60??GeV/c, using charged tracks with transverse momentum ptrkT>1??GeV/c in a cone around the jet axis. The association with an isolated photon constrains the initial pT and azimuthal angle of the parton whose shower produced the jet. For central Pb-Pb 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 Pb-Pb events show an excess (depletion) of low (high) pT particles, with a transition around 3??GeV/c. This measurement shows for the first time the in-medium shower modifications of partons (quark dominated) with well-defined initial kinematics. It constitutes a new well-controlled reference for testing theoretical models of the parton passage through the quark-gluon plasma.
Açıklama
Anahtar Kelimeler
Relativistic heavy-ion collisions, Particle correlations & fluctuations, Photon lepton, quark production
Kaynak
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
Sayı
Künye
PHYSICAL REVIEW LETTERS 121, 242301 (2018)
