On the nuclear modification factor at RHIC and LHC

Andrey Kormilitzin, Eugene Levin, Amir H. Rezaeian*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We show that pQCD factorization incorporated with pre-hadronization energy-loss effect naturally leads to flatness of the nuclear modification factor RAA for produced hadrons at high transverse momentum pT. We consider two possible scenarios for the pre-hadronization: In scenario 1, the produced gluon propagates through dense QCD medium and loses energy. In scenario 2, all gluons first decay to quark-antiquark pairs and then each pair loses energy as propagating through the medium. We show that the estimates of the energy-loss in these two different models lead to very close values and is able to explain the suppression of high-pT hadrons in nucleus-nucleus collisions at RHIC. We show that the onset of the flatness of RAA for the produced hadron in central collisions at midrapidity is about pT≈15 and 25 GeV at RHIC and the LHC energies, respectively. We show that the smallness (RAA<0.5) and the high-pT flatness of RAA obtained from the kT factorization supplemented with the Balitsky-Kovchegov (BK) equation is rather generic and it does not strongly depend on the details of the BK solutions. We show that energy-loss effect reduces the nuclear modification factor obtained from the kT factorization about 30-50% at moderate pT.

Original languageEnglish
Pages (from-to)84-101
Number of pages18
JournalNuclear Physics A
Issue number1
StatePublished - 15 Jun 2011


FundersFunder number
Conicyt Programa BicentenarioPSD-91-2006
Fondo Nacional de Desarrollo Científico y Tecnológico1100648, 1090312


    • Hadron production
    • Heavy ion physics
    • LHC
    • PQCD


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