1,937 research outputs found
J/psi suppression at SPS and RHIC in the comovers approach
The NA50 collaboration data on the suppression are compared with the
results obtained in a comovers approach based on the Dual Parton Model (DPM).
Predictions for the suppression versus the charged multiplicity -
measured in the rapidity region of the dimuon trigger - are given for SPS and
RHIC energies.Comment: 4 pages, contribution to QM200
Impact of the Nuclear Modification of the Gluon Densities on J/Psi production in pPb collisions at sqrt(s_NN) = 5 TeV
We update our previous studies of nuclear-matter effects on J/Psi production
in proton-nucleus for the recent LHC pPb runs at sqrt(s_NN)=5 TeV. We have
analysed the effects of the modification of the gluon PDFs in nucleus, using an
exact kinematics for a 2->2 process, namely g+g->J/Psi+g as expected from LO
pQCD. This allows to constrain the transverse-momentum while computing the
nuclear modification factor for different rapidities, unlike with the usual
simplified kinematics. Owing to the absence of measurement in pp collisions at
the same sqrt(s_NN) and owing to the expected significant uncertainties in
yield interpolations which would hinder definite interpretations of nuclear
modification factor --R_pPb--, we have derived forward-to-backward and
central-to-peripheral yield ratios in which the unknown proton-proton yield
cancel. These have been computed without and with a transverse-momentum cut,
e.g. to comply with the ATLAS and CMS constraints in the central-rapidity
region.Comment: 5 pages, 16 figures, LaTeX. v2: predictions on R_CP and 3 references
added; introduction slightly extende
J/\psi\ and \psi' production in proton(deuteron)-nucleus collisions: lessons from RHIC for the proton-lead LHC run
We study the impact of different cold nuclear matter effects both on J/\psi\
and \psi' production, among them the modification of the gluon distribution in
bound nucleons, commonly known as gluon shadowing, and the survival probability
for a bound state to escape the nucleus --the nuclear absorption. Less
conventional effects such as saturation and fractional energy loss are also
discussed. We pay a particular attention to the recent PHENIX preliminary data
on \psi' production in dAu collisions at sqrt{s}=200 GeV, which show a strong
suppression for central collisions, 5 times larger than the one obtained for
J/\psi\ production at the same energy. We conclude that none of the
abovementioned mechanisms can explain this experimental result.Comment: 4 pages, 2 tables, 2 figures, contribution to Rencontres du Vietnam,
'Heavy Ion Collisions in the LHC Era', 15-21 July 2012, Quy Nhon, Vietna
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