Energy dependence of {pi}{sub {+-}},p and {bar p} transverse momentum spectra for Au+Au collisions at {radical}{ovr s}{sub NN} = 62.4 and 200 GeV.

Journal Article · Mon Oct 01 00:00:00 EDT 2007 · Phys. Lett. B

DOI:https://doi.org/10.1016/j.physletb.2007.06.035· OSTI ID:966341

Abelev, B I; Aggarwal, M M; Ahammed, Z; Anderson, B D; Arkhipkin, D; Krueger, K; Spinka, H M; Underwood, D G; Univ, Panjab

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

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF); BMBF - Germany; CNRS/IN2P3, RA, PRL - France; EP-SRC - United Kingdom; FAPESP - Brazil
• DOE Contract Number: DE-AC02-06CH11357
• OSTI ID: 966341
• Report Number(s): ANL-HEP-PR-09-100; PYLBAJ; TRN: US0903947
• Journal Information: Phys. Lett. B, Vol. 655, Issue 3-4 ; Oct. 2007; ISSN 0370-2693
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COALESCENCE
ENERGY DEPENDENCE
MODIFICATIONS
PIONS
PROTONS
QUARKS
QUENCHING
RECOMBINATION
SPECTRA
TRANSVERSE MOMENTUM