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Title: Cold nuclear matter effects in J/(psi) production

Abstract

Lattice QCD predicts that, above a certain critical energy density or temperature, strongly interacting matter undergoes a phase transition from the hadronic world to a quark-gluon plasma state, where the coloured quarks and gluons are no longer bound to colourless hadrons. The suppression of quarkonium production in high-energy nuclear collisions is one of the most interesting signatures of QGP formation, for two reasons: due to their large masses, charm and beauty quarks are created only in the initial hard scattering processes, before the QGP is formed; and the Q{bar Q} binding potential should be screened in the deconfined colour medium. Until the LHC starts colliding Pb nuclei, charm is the heaviest quark that can check the validity of the finite temperature QCD predictions, given the much smaller beauty production cross sections. However, the interpretation of the presently available results on charmonium suppression in heavy-ion collisions, obtained at the SPS and RHIC, is hampered by a multitude of other 'nuclear effects', which exist even in the absence of QGP formation, such as the badly understood nuclear modifications of the gluon distribution functions, the level of energy lost by the partons traversing the nuclei before producing the Q{bar Q} pair, the ratemore » at which the nascent quarkonium state is broken up by the surrounding nuclear matter, etc. Fortunately, most of these 'cold nuclear matter' effects can be studied on the basis of proton-nucleus measurements. However, care must be taken when converting the p-A observations into a reference baseline that can be used in the analysis of the heavy-ion data. In particular, it has recently been shown [1] that it is wrong to assume that the rate of final-state Glauber-like J/{psi} absorption, usually called the 'J/{psi} absorption cross section', {sigma}{sub abs}{sup J/{psi}}, is independent of the collision energy and of the charmonium kinematics, as was previously assumed in the analysis of the SPS heavy-ion data.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
957165
Report Number(s):
LLNL-CONF-413585
TRN: US1002290
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Presented at: XLVII International Winter Meeting on Nuclear Physics, Bormio, Italy, Jan 26 - Jan 30, 2009
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ABSORPTION; CHARMONIUM; CROSS SECTIONS; DISTRIBUTION FUNCTIONS; ENERGY DENSITY; GLUONS; HADRONS; MODIFICATIONS; NUCLEAR MATTER; NUCLEAR PHYSICS; NUCLEI; PRODUCTION; QUANTUM CHROMODYNAMICS; QUARK MATTER; QUARKONIUM; QUARKS; SCATTERING

Citation Formats

Wohri, H K, Faccioli, P, Lourenco, C, and Vogt, R. Cold nuclear matter effects in J/(psi) production. United States: N. p., 2009. Web.
Wohri, H K, Faccioli, P, Lourenco, C, & Vogt, R. Cold nuclear matter effects in J/(psi) production. United States.
Wohri, H K, Faccioli, P, Lourenco, C, and Vogt, R. Mon . "Cold nuclear matter effects in J/(psi) production". United States. https://www.osti.gov/servlets/purl/957165.
@article{osti_957165,
title = {Cold nuclear matter effects in J/(psi) production},
author = {Wohri, H K and Faccioli, P and Lourenco, C and Vogt, R},
abstractNote = {Lattice QCD predicts that, above a certain critical energy density or temperature, strongly interacting matter undergoes a phase transition from the hadronic world to a quark-gluon plasma state, where the coloured quarks and gluons are no longer bound to colourless hadrons. The suppression of quarkonium production in high-energy nuclear collisions is one of the most interesting signatures of QGP formation, for two reasons: due to their large masses, charm and beauty quarks are created only in the initial hard scattering processes, before the QGP is formed; and the Q{bar Q} binding potential should be screened in the deconfined colour medium. Until the LHC starts colliding Pb nuclei, charm is the heaviest quark that can check the validity of the finite temperature QCD predictions, given the much smaller beauty production cross sections. However, the interpretation of the presently available results on charmonium suppression in heavy-ion collisions, obtained at the SPS and RHIC, is hampered by a multitude of other 'nuclear effects', which exist even in the absence of QGP formation, such as the badly understood nuclear modifications of the gluon distribution functions, the level of energy lost by the partons traversing the nuclei before producing the Q{bar Q} pair, the rate at which the nascent quarkonium state is broken up by the surrounding nuclear matter, etc. Fortunately, most of these 'cold nuclear matter' effects can be studied on the basis of proton-nucleus measurements. However, care must be taken when converting the p-A observations into a reference baseline that can be used in the analysis of the heavy-ion data. In particular, it has recently been shown [1] that it is wrong to assume that the rate of final-state Glauber-like J/{psi} absorption, usually called the 'J/{psi} absorption cross section', {sigma}{sub abs}{sup J/{psi}}, is independent of the collision energy and of the charmonium kinematics, as was previously assumed in the analysis of the SPS heavy-ion data.},
doi = {},
url = {https://www.osti.gov/biblio/957165}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2009},
month = {6}
}

Conference:
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