High transverse momentum (pT>2 GeV/c) hadrons provide an excellent probe of nuclear matter at high energy density created in relativistic heavy ion collisions as they are predicted to arise from quark and gluon fragmentation in initial parton-parton scattering. In absence of medium effects, high pT hadron yield should scale with the number of inelastic nucléon-nucléon collisions However theoretical studies have suggested that partons could lose a significant fraction of their energy in high density gluonic nucleon via gluon bremsstrahlung.
One of the must intriguing observations at Relativistic Heavy Ion Collider (RHIC, BNL, USA) is the suppression of high pT hadrons in central Au+Au collisions at 130 and 200 A GeV. The objective of this proposal is to improve our experimental knowledge of high pT hadron production in Au + Au and d + Au collision at 200 A GeV. This work wille be performed in the framework of the PHENIX experiment  at RHIC. During 2003 (run - 3), the RHIC collider delivered deuteron and gold beams at 100 A GeV, and an integrated luminosity of 2.7 nb-1 was sampled by PHENIX experiment. The full analysis of this data will be performed during following year, but preliminary results are already very promising. Next year (run - 4) RHIC collider will deliver a 100 A GeV gold beam at high luminosity.
This will allow exploring the hadron suppression at very high pT (pT> 10 GeV) where theoretical predictions would be more reliable. The applicant will develop this research the PH ENIX group at SUBATECH.  M. Gyulassy et al., Phys. Lett B243 (1990) 432X. N. Wan et al., Phys Rev. Lett. 68 (1192) 1480  R. J. Glauber et al., Nucí. Phys. B21 (1970) 135  PHENIX Collaboration, Phys. Rev. Lett 88 (2002) 022301PHENIX Collaboratio n, Phys. Lett B561 (2003) 82PHENIX Collaboration, Phys. Rev. Lett 89 (2002) 202301PHENIX Collaboration, nucl-ex / 0304022 (2003)  PHENIX Collaboration, NIM A 499 (2003)
Call for proposal
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