The new physics at RHIC. From transparency to high p_t suppression

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• 作者：J.J. Gaardh&#xf8 ; je ; I. Arsene ; I.G. Bearden ; D. Beavis ; C. Besliu ; B. Budick ; H. B&#xf8 ; ggild ; C. Chasman ; C.H. Christensen ; P. Christiansen ; J. Cibor ; R. Debbe ; E. Enger ; J.J. Gaardh&#xf8 ; je ; M. Germinario ; K. Hagel ; O. Hansen ; A. Holm ; H. Ito ; A. Jipa ; et al.
• 刊名：Nuclear Physics A
• 出版年：2004
• 出版时间：5 April 2004
• 年：2004
• 卷：734
• 期：Complete
• 页码：13-27
• 全文大小：942 K

文摘

Heavy ion collisions at RHIC energies (Au + Au collisions at√S_NN = 200GeV) exhibit significant new features as compared to earlier experiments at lower energies. The reaction is characterized by a high degree of transparency of the collision partners leading to the formation of a baryon-poor central region. In this zone, particle production occurs mainly from the stretching of the color field. The initial energy density is well above the one considered necessary for the formation of the Quark Gluon Plasma, QGP. The production of charged particles of various masses is consistent with chemical and thermal equilibrium. Recently, a suppression of the high transverse momentum component of hadron spectra has been observed in central Au + Au collisions. This can be explained by the energy loss experienced by leading partons in a medium with a high density of unscreened color charges. In contrast, such highp_t jets are not suppressed in d + Au collisions suggesting that the highp_t suppression is not due to initial state effects in the ultrarelativistic colliding nuclei.