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J/psi suppression and elliptic flow in 200~GeV Au+Au collisions at the mid rapidity region of the PHENIX experiment

Abstract : J/psi are considered to be one of the key probes of the Quark Gluon Plasma (QGP) formation in heavy ion collisions. Color screening was proposed as a mechanism leading to anomalous suppression beyond normal absorption in nuclear matter if J/psi were created in a deconfined medium, providing a direct evidence of deconfinement. The PHENIX detector is one of the four experiments that were installed at RHIC, with a design that is optimal for the measurement of the J/psi meson at forward rapidity in the dimuon decay channel, and at mid rapidity in the dielectron decay channel. The work presented here covers the analysis of data taken by the mid rapidity spectrometers of PHENIX in Au+Au collisions at 200 GeV. The nuclear modification factor is measured as a function of centrality, and compared to estimations of cold nuclear matter suppression. Though the suppression seen in the most central collisions goes up to a factor of more than three, most of it can possibly be accounted for by cold nuclear effects, and the significance of the extra anomalous suppression is small. Comparisons to the CERN SPS results and to the suppression measurement at forward rapidity in PHENIX have led to the speculation that regeneration, a J/psi production mechanism by association of uncorrelated c and c-bar quarks, might be at play in central heavy ion collisions. A second measurement presented in this thesis, the elliptic flow of J/psi as a function of pT, is a potential tool to test the regeneration scenario. Though lack of statistics hinders the establishment of firm conclusions, the result is a good proof of principle of the feasibility of the measurement in a high multiplicity environment.
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Contributor : Ermias Tujuba Atomssa Connect in order to contact the contributor
Submitted on : Thursday, May 14, 2009 - 5:09:34 PM
Last modification on : Wednesday, March 27, 2019 - 4:40:21 PM
Long-term archiving on: : Thursday, June 10, 2010 - 9:24:39 PM


  • HAL Id : tel-00384294, version 1



Ermias Tujuba Atomssa. J/psi suppression and elliptic flow in 200~GeV Au+Au collisions at the mid rapidity region of the PHENIX experiment. High Energy Physics - Experiment [hep-ex]. Ecole Polytechnique X, 2008. English. ⟨tel-00384294⟩



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