Energy dependence of pi, p and pbar transverse momentum spectra for Au+Au collisions at sqrt sNN = 62.4 and 200 GeV

Journal Article · Mon Mar 26 04:00:00 EDT 2007 · Physical Letters B

OSTI ID:936577

Ritter, H

We study the energy dependence of the transverse momentum (pT) spectra for charged pions, protons and anti-protons for Au+Au collisions at sqrt sNN = 62.4 and 200 GeV. Data are presented at mid-rapidity (lbar y rbar< 0.5) for 0.2< pT< 12 GeV/c. In the intermediate pT region (2< pT< 6 GeV/c), the nuclear modification factor is higher at 62.4 GeV than at 200 GeV, while at higher pT (pT> 7 GeV/c) the modification is similar for both energies. The p/pi+ and pbar/pi- ratios for central collisions at sqrt sNN = 62.4 GeV peak at pT _~;; 2 GeV/c. In the pT range where recombination is expected to dominate, the p/pi+ ratios at 62.4 GeV are larger than at 200 GeV, while the pbar/pi- ratios are smaller. For pT> 2 GeV/c, the pbar/pi- ratios at the two beam energies are independent of pT and centrality indicating that the dependence of the pbar/pi- ratio on pT does not change between 62.4 and 200 GeV. These findings challenge various models incorporating jet quenching and/or constituent quark coalescence.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Nuclear Science Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 936577
• Report Number(s): LBNL-824E
• Journal Information: Physical Letters B, Journal Name: Physical Letters B
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COALESCENCE
ENERGY DEPENDENCE
MODIFICATIONS
PIONS
PROTONS
Particle production
recombination
fragmentation
jet quenching
QUARKS
QUENCHING
RECOMBINATION
SPECTRA
TRANSVERSE MOMENTUM