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Title: Dihadron Tomography of High-Energy Nuclear Collisions inNext-to-Leading Order Perturbative QCD

Journal Article · · Physical Review Letters

Back-to-back dihadron spectra in high-energy heavy-ioncollisions are studied within the next-to-leading order (NLO)perturbative QCD parton model with jet quenching incorporated viamodified jet fragmentation functions due to radiative parton energy lossin dense medium. The experimentally observed appearance of back-to-backdihadron sat high p_T is found to originate mainly from jet pairsproduced close and tangential to the surface of the dense matter.However, a substantial fraction of observed high p_T dihadrons also comesfrom jets produced at the center of the medium after losing finite amountof energy. Consequently, the suppression factor of such high-p_T hadronpairs is foundto be more sensitive to the initial gluon density than thesingle hadron spectra that are dominated by surface emission. Asimultaneous chi2-fit to both the single and dihadron spectra can beachieved within an arrow range of the energy loss parametersepsilon_0=1.6-2.1 GeV/fm. Because of the flattening of the initial jetproduction spectra, high p_T dihadrons at the LHC energy are found to bemore robust as probes of the dense medium.

Research Organization:
COLLABORATION - Huazhong NormalU./China
DOE Contract Number:
DE-AC02-05CH11231
OSTI ID:
923204
Report Number(s):
LBNL-62151; PRLTAO; R&D Project: NTCOST; BnR: KB0301020; TRN: US0801791
Journal Information:
Physical Review Letters, Vol. 98; Related Information: Journal Publication Date: 25 May 2007; ISSN 0031-9007
Country of Publication:
United States
Language:
English