The p/π ratio p _T dependence in the RHIC range of baryo-chemical potential

Abstract

The BRAHMS measurement of proton-to-pion ratios in Au+Au and p+p collisions at $\sqrt {s_{NN} }$ = 62.4 GeV and $\sqrt {s_{NN} }$ = 200 GeV is presented as a function of transverse momentum and collision centrality within the pseudorapidity range 0 ≤ η ≤ 3. The baryo-chemical potential, µ _B , for the indicated data spans from µ _B ≈ 26 MeV ($\sqrt {s_{NN} }$ 200 GeV, η ≈ 0) to µ _B ∼ 260 MeV ($\sqrt {s_{NN} }$= 62.4 GeV, η ≈ 3) [1]. The p/πratio measured for Au+Au system at $\sqrt {s_{NN} }$ 62.4 GeV, η ≈ 3 reaches astounding value of 8–10 at p _T > 1.5 GeV/c. For these energy and pseudorapidity interval no centrality dependency of p/π ratio is observed. Moreover, the baryon-to-meson ratio of nucleus-nucleus data are consistent with results obtained for p+p interactions.