26-30 March 2012
University of Bonn
Europe/Berlin timezone

J/psi Photoproduction in ultra-peripheral Au+Au collisions measured by RHIC-PHENIX.

28 Mar 2012, 14:06
18m
Drawing Room, Mathematical Institute (University of Bonn)

Drawing Room, Mathematical Institute

University of Bonn

Heavy flavours Heavy flavours

Speaker

Mr Akihisa Takahara (CNS, University of Tokyo and JRA RIKEN)

Description

Title:J/psi Photoproduction in ultra-peripheral Au+Au collisions measured by RHIC-PHENIX. Ultra-peripheral collisions are heavy-ion collisions with impact parameter larger than twice the nuclear radius. Since there is no nuclear overlap, strong interactions cannot occur and ions interact through photon-ion (coherent), photon-nucleus (incoherent), and photon photon collisions. Measurement of vector meson photo production is a sensitive probe of gluon distribution in nuclei. At RHIC energy, measurement of J$/\psi$ photo production corresponds to x $\cong$ 0.015 and Q$^{2}$ =2.5 $GeV/c^2$. In the kinematic region, nuclear shadowing plays an important role and that still have large uncertainty. PHENIX has the capability of measuring J$/\psi$'s via their dielectron decays at mid-rapidity ($|y|<0.35$) and dimuon decays at forward (1.2$<|y|<$2.2) rapidity. PHENIX published J$/\psi$ photo production cross section at mid-rapidity in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV in the 2004 dataset [1] (add reference in the end). The measured cross section was found to be consistent with theoretical calculations within its statistical error. PHENIX collected higher statistics Au+Au collisions datasets in 2007 and 2010 that allow a more precise measurement over a wider rapidity range. In this talk I will present present new preliminary results for the integrated and differential cross section of UPC J$/\psi$ at central and forward rapidity.

Primary author

Mr Akihisa Takahara (CNS, University of Tokyo and JRA RIKEN)

Presentation Materials