J/psi polarization in 800-GeV p-Cu interactions.
ABSTRACT We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).
Full-textDOI: · Available from: R. Tribble, May 30, 2015
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ABSTRACT: The study of nuclear effects for J/ψ production in proton–nucleus collisions is crucial for a correct interpretation of the J/ψ suppression patterns experimentally observed in heavy-ion collisions. By means of three representative sets of nuclear parton distribution, the energy loss effect in the initial state and the nuclear absorption effect in the final state are taken into account in the uniform framework of the Glauber model. A leading order phenomenological analysis is performed on J/ψ production cross-section ratios R W/Be (x F) for the E866 experimental data. The J/ψ suppression is investigated quantitatively due to the different nuclear effects. It is shown that the energy loss effect with resulting in the suppression on R W/Be (x F) is more important than the nuclear effects on parton distributions in high x F region. The E866 data in the small x F keep out the nuclear gluon distribution with a large anti-shadowing effect. However, the new HERA-B measurement is not in support of the anti-shadowing effect in the nuclear gluon distribution. It is found that the J/ψ–nucleon inelastic cross section depends on the kinematical variable x F, and increases as x F in the region x F>0.2.European Physical Journal C 05/2010; 67(1):173-179. DOI:10.1140/epjc/s10052-010-1270-1 · 5.44 Impact Factor
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ABSTRACT: The study of dilepton production in heavy-ion collisions at the CERN SPS provided some of the most interesting observations done so far in the search for the quark gluon plasma. However, several aspects of the understanding of these measurements need to be clarified. For example, the study of the J/ $\psi$ production in different colliding systems should help to disentangle which is the variable driving the J/ $\psi$ suppression. The NA60 experiment, with a new radiation tolerant Silicon pixel detector, studied Indium-Indium interactions in the year 2003. In this paper, we present the J/ $\psi$ / DY ratio, integrated over all the centralities of the collisions, together with a first study of the J/ $\psi$ transverse momentum and polarization.European Physical Journal C 08/2005; 43(1-4). DOI:10.1140/epjc/s2005-02208-y · 5.44 Impact Factor
Article: J/psi and open charm production[Show abstract] [Hide abstract]
ABSTRACT: An overview of J/psgr and open charm production is presented, concentrating primarily on experimental results that have come out over the past few years.Journal of Physics G Nuclear and Particle Physics 08/2004; 30(8):861-. DOI:10.1088/0954-3899/30/8/027 · 2.84 Impact Factor