Rapidity dependence of the proton-to-pion ratio in Au+Au and p+p collisions at and 200 GeV

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• 作者：BRAHMS Collaboration ; I.G. Arsene ; I.G. Bearden ; D. Beavis ; S. Bekele ; C. Besliu ; B. Budick ; H. B&#xf8 ; ggild ; C. Chasman ; C.H. Christensen ; P. Christiansen ; H.H. Dalsgaard ; R. Debbe ; J.J. Gaardh&#xf8
• 关键词：Heavy ion collision ; Particle ratios ; Forward rapidity ; Hadronization
• 刊名：Physics Letters B
• 出版年：2010
• 出版时间：1 February 2010
• 年：2010
• 卷：684
• 期：1
• 页码：22-27
• 全文大小：361 K

文摘

The proton-to-pion ratios measured in the BRAHMS experiment for Au+Au and p+p collisions at 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_T-dependence of the p/π⁺ ratios measured in Au+Au collisions at and η≈2.2 with the same ratio measured at and η=0. The great similarity found between these ratios throughout the whole p_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 μ_B. At the collision energy of 62.4 GeV, we have observed a unique point in pseudorapidity, η=3.2, where the p/π⁺ ratio is independent of the collision system size in a wide p_T-range of 0.3p_T1.8 GeV/c.