/ Experiment-Nucl nucl-ex/0601042

Measurements of identified particles at intermediate transverse momentum in the STAR experiment from Au + Au collisions at s(NN)**(1/2) =200- GeV

Adams, John ; Aggarwal, M.M. ; Ahammed, Z. ; Amonett, J. ; Anderson, B.D. ; Anderson, M. ; Arkhipkin, D. ; Averichev, G.S. ; Badyal, S.K. ; Bai, Y. ; Balewski, J. ; Barannikova, O. ; Barnby, L.S. ; Baudot, J. ; Bekele, S. ; Belaga, V.V. ; Bellingeri-Laurikainen, A. ; Bellwied, R. ; Bezverkhny, B.I. ; Bharadwaj, S. ; Bhasin, A. ; Bhati, A.K. ; Bichsel, H. ; Bielcik, J. ; Bielcikova, J.

Published in: Phys.Rev.C
Pages: 15

Abstract: Data for Au+Au collisions at sqrt{s_{NN}}=200 GeV are analyzed to determine the ratios of identified hadrons ($\pi$, $K$, $p$, $\Lambda$) as functions of collision centrality and transverse momentum ($p_T$). We find that ratios of anti-baryon to baryon yields are independent of $p_T$ up to 5 GeV/c, a result inconsistent with results of theoretical pQCD calculations that predict a decrease due to a stronger contribution from valence quark scattering. For both strange and non-strange species, strong baryon enhancements relative to meson yields are observed as a function of collision centrality in the intermediate $p_T$ region, leading to $p/\pi$ and $\Lambda$/K ratios greater than unity. The increased $p_T$ range offered by the $\Lambda$/K$^{0}_{S}$ ratio allows a test of the applicability of various models developed for the intermediate $p_{T}$ region. The physics implications of these measurements are discussed with regard to different theoretical models.

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