Rapidity Dependence of the proton-to-pion ratio in Au+Au and p+p collisions at sqrt NN = 62.4 and GeV
The proton-to-pion ratios measured in the BRAHMS experiment for Au+Au and p+p collisions at {radical}s{sub NN} = 62.4 and 200 GeV are presented as a function of transverse momentum and collision centrality at selected pseudorapidities in the range of 0-3.8. A strong pseudorapidity dependence of these ratios is observed. We also compare the magnitude and p{sub T}-dependence of the p/{pi}{sup +} ratios measured in Au+Au collisions at {radical}s{sub NN} = 200 GeV and {eta} {approx} 2.2 with the same ratio measured at {radical}s{sub NN} = 62.4 and {eta} = 0. The great similarity found between these ratios throughout the whole p{sub T} range (up to 2.2 GeV/c) is consistent with particle ratios in A+A collisions being described with grand-canonical distributions characterized by the baryo-chemical potential {mu}B. At the collision energy of 62.4 GeV, we have observed a unique point in pseudorapidity, {eta} = 3.2, where the p/{pi}{sup +} ratio is independent of the collision system size in a wide p{sub T}-range of 0.3 {le} p{sub T} {le} 1.8 GeV/c.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). Relativistic Heavy Ion Collider (RHIC)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1040433
- Report Number(s):
- BNL-93621-2010-JA; PYLBAJ; R&D Project: PO-003; KB0201021; TRN: US1202440
- Journal Information:
- Physics Letters, (Section) B, Vol. 684, Issue 1; ISSN 0370-2693
- Country of Publication:
- United States
- Language:
- English
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