298 articles – 2257 Notices  [english version]
 HAL : in2p3-00145423, version 1
 arXiv : nucl-ex/0611006
 Physical Review C 75 (2006) 024909
 High transverse momentum $\eta$ meson production in p+p, d+Au and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV
 PHENIX Collaboration(s)
 (2006)
 Inclusive transverse momentum spectra of eta mesons in the range p_T~2-12 GeV/c have been measured at mid-rapidity (|\eta| < 0,35) by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions at sqrt(s_NN) = 200 GeV. The eta mesons are reconstructed through their eta--> \gamma\gamma channel for the three colliding systems as well as through the eta-->pi^0 pi+ pi- decay mode in p+p and d+Au collisions. The nuclear modification factor in d+Au collisions, R_dAu(p_T~1.0-1.1, suggests at most only modest p_T broadening ("Cronin enhancement"). In central Au+Au reactions, the eta yields are significantly suppressed, with R_AuAu(pT)~0.2. The ratio of eta to pi^0 yields is approximately constant as a function of p_T for the three colliding systems in agreement with the high-p_T world average of R_eta/pi^0 \approx 0.5 in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions for a wide range of center-of-mass energies [sqrt(s_NN)~3-1800 GeV] as well as, for high scaled momentum x_p, in e+e- annihilations at sqrt(s)=91.2 GeV. These results are consistent with a scenario where high-p_T eta production in nuclear collisions at RHIC is largely unaffected by initial-state effects, but where light-quark mesons (pi^0;eta) are equally suppressed due to final-state interactions of the parent partons in the dense medium produced in Au+Au reactions.
 Thème(s) : Physique/Physique Nucléaire Expérimentale
 Lien vers le texte intégral : http://fr.arXiv.org/abs/nucl-ex/0611006
 in2p3-00145423, version 1 http://hal.in2p3.fr/in2p3-00145423 oai:hal.in2p3.fr:in2p3-00145423 Contributeur : Dominique Girod <> Soumis le : Jeudi 10 Mai 2007, 11:32:49 Dernière modification le : Jeudi 10 Mai 2007, 14:33:53