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

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}...

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Bibliographic Details
Published in:	Physics letters. B 2007-10, Vol.655 (3-4 ; Oct. 2007)
Main Authors:	Abelev, B. I., Aggarwal, M. M., Ahammed, Z., Anderson, B. D., Arkhipkin, D., Krueger, K., Spinka, H. M., Underwood, D. G., High Energy Physics, Univ. of Illinois, Panjab Univ, Varible Energy Cyclotron Centre, Kent State Univ, Particle Physics Lab, STAR Collaboration
Format:	Article
Language:	eng
Subjects:	COALESCENCE ENERGY DEPENDENCE MODIFICATIONS PHYSICS OF ELEMENTARY PARTICLES AND FIELDS PIONS PROTONS QUARKS QUENCHING RECOMBINATION SPECTRA TRANSVERSE MOMENTUM
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Summary:	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.
ISSN:	0370-2693 1873-2445