Rapidity Dependence of the proton-to-pion ratio in Au+Au and p+p collisions at sqrt NN = 62.4 and GeV

Journal Article · Tue May 12 04:00:00 EDT 2009 · Physics Letters, (Section) B

OSTI ID:1040433

Arsene, I G; Videbaek, F

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 Laboratory (BNL) Relativistic Heavy Ion Collider
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1040433
• Report Number(s): BNL--93621-2010-JA; KB0201021
• Journal Information: Physics Letters, (Section) B, Journal Name: Physics Letters, (Section) B Journal Issue: 1 Vol. 684; ISSN PYLBAJ; ISSN 0370-2693
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
HEAVY IONS
ION COLLISIONS
PARTICLE RAPIDITY
TRANSVERSE MOMENTUM
relativistic heavy ion collider