The production of in 200 GeV/nucleon oxygen-uranium interactions

Baglin, C.; Bussiére, A.; Guillaud, J.P.; Ogren, H. O.; Staley, F.; Baldit, A.; Castor, J.; Devaux, A.; Fargeix, J.; Felgeyrolles, X.; Force, P.; Fredj, L.; Landaud, G.; Sonderegger, P.; Abreu, M.C.; Barreira, G.; Bordalo, P.; Casaca, Augusto; Ferraz, A. C.; Ferreira, R.; Gago, J.; Gomes, Pedro S.; Lourenço, C.; Maio, A.; Peralta, L.; Pimenta, M.; Ramos, S.; Varela, J.; Gerschel, C.; Sinquin, A.; Borenstein, S.; Busson, P.; Charlot, C.; Chaurand, B.; Kluberg, L.; Romana, A.; Salmeron, R.; Britz, J.; Gorodetzky, P.; Kraus, L.; Linck, I.; Racca, C.; Cases, R.; Alimi, M.; Bedjidian, M.; Contardo, D.; Descroix, E.; Drapier, O.; Grossiord, J.‐Y.; Guichard, A.; Haroutunian, R.; Pizzi, J.R.

doi:10.1016/0370-2693(89)90905-2

Cited by 200 publications

(44 citation statements)

References 9 publications

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“…Once it is fixed, we have to check that the collision geometry (the measured relation between E T and the number of spectator nucleons, the measured E T -distribution) is correctly reproduced [52]. When this is assured, we can check if the J/ψ production in O−Cu, O−U and S−U, as measured by the NA38 experiment at CERN over the past ten years [100,104], shows anything beyond the expected pre-resonance nuclear absorption with the cross section σ ccg−N = 6.9 ± 1.1 mb determined from p − A interactions. The answer is clearly negative, as seen in Fig.…”

Section: Pre-resonance Suppressionmentioning

confidence: 99%

“…The traversed medium of nucleus A is parametrized through a Woods-Saxon density distribution ρ A (z), and by comparing S A ccg with data for different targets A, the dissociation cross section for ccg − N interactions is found to be [103] σ ccg−N = 6.9 ± 1.1 mb. Figure 32: J/ψ and ψ production in nuclear collisions, compared to pre-resonance absorption in nuclear matter [100,104].…”

Section: Pre-resonance Suppressionmentioning

confidence: 99%

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Colour deconfinement in nuclear collisions

2000

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Abstract:QCD predicts that strongly interacting matter will undergo a transition from a state of hadronic constituents to a plasma of unbound quarks and gluons. We first survey the conceptual features of this transition and its description in finite temperature lattice QCD, before we address its experimental investigation through high energy nucleus-nucleus collisions. After considering the conditions achievable in such collisions, we discuss the possible probes to check if the produced medium in its early stages was indeed deconfined. We then elaborate the method that has emerged and the results which were obtained using the most extensively studied deconfinement probe, the suppression of charmonium production. In closing, we discuss possible supporting information provided through the study of soft hadronic probes.

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Section: Pre-resonance Suppressionmentioning

confidence: 99%

Section: Pre-resonance Suppressionmentioning

confidence: 99%

Colour deconfinement in nuclear collisions

2000

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“…The suppression of J/ψ production was observed quite early in the CERN heavy ion program [26]; but it was soon noted that it occurs as well already in p-A collisions (see Fig. 2), where it inceases with increasing A [27]- [29].…”

Section: Charmonium Suppressionmentioning

confidence: 99%

The Search for the Qgp: A Critical Appraisal

Satz

2001

Nucleus–Nucleus Collisions

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Abstract:Over the past 15 years, an extensive program of high energy nuclear collisions at BNL and CERN was devoted to the experimental search for the quark-gluon plasma predicted by QCD. The start of RHIC this year will increase the highest available collision energy by a factor 10. This seems a good time for a critical assessment: what have we learned so far and what can we hope to learn in the coming years?

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“…Their, by now wellknown, idea is that the Debye screening of the gluon exchanges will make the binding of heavy quarks into the bound states impossible or unlikely once a sufficiently high temperature is reached. The lack of quarkonium states would thus signal deconfinement; this effect was indeed observed and studied in detail at CERN SPS by the NA38 [2] and NA50 Collaborations [3]. The results on J/ψ production at RHIC have recently been presented by the PHENIX Collaboration [4].…”

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confidence: 91%

Quarkonium polarization in heavy ion collisions as a possible signature of the quark-gluon plasma

Ioffe

Kharzeev

2003

Phys. Rev. C

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The polarization of quarkonium states produced in hadron collisions exhibits strong non-perturbative effects -for example, at small transverse momentum pt charmonia appear unpolarized, in sharp contradiction to the predictions of perturbation theory. The quark-gluon plasma is expected to screen away the non-perturbative physics; therefore those quarkonia which escape from the plasma should possess polarization as predicted by perturbative QCD. We estimate the expected J/ψ polarization at small pt, and find that it translates into the asymmetry of the e + e − (µThe possibility to form quark-gluon plasma in heavy ion collisions is an intriguing problem of strong interaction physics. To establish the formation of plasma, a number of signatures were proposed; here we will concentrate on heavy quarkonia. Suppression of heavy quarkonium states has been suggested long time ago by Matsui and Satz [1] as a signature of the deconfinement phase transition in heavy ion collisions. Their, by now wellknown, idea is that the Debye screening of the gluon exchanges will make the binding of heavy quarks into the bound states impossible or unlikely once a sufficiently high temperature is reached. The lack of quarkonium states would thus signal deconfinement; this effect was indeed observed and studied in detail at CERN SPS by the NA38 [2] and NA50 Collaborations [3]. The results on J/ψ production at RHIC have recently been presented by the PHENIX Collaboration [4]. The observations of quarkonium suppression have been interpreted as a signal of quark-gluon plasma formation [5]. However, different conclusions were reached in [6], where it was argued that the effect may arise due to quarkonium collisions with the comoving hadrons. Additional tests of the quark-gluon plasma formation could help to clarify the situation.In this note we propose to use for the diagnostics of the quark-gluon plasma those heavy quarkonia which escape from it. This would require experimental measurements of quarkonium polarization, which can be reconstructed from the angular distributions of quarkonium decaysdileptons and/or photons. For J/ψ states, one would need to measure the angular distribution of electrons (or muons) in the J/ψ → e + e − decay in J/ψ rest frame relative to the direction of its momentum. (We will concentrate on J/ψ's at relatively small p t , which dominate the total production cross section.)Let us first formulate what we mean by the quarkgluon plasma, since different definitions sometimes may result in misunderstanding. We define the quark-gluon plasma as a gas of quarks and gluons in which the interactions can be described by perturbative QCD and non-perturbative effects are either absent or can be neglected. We will not need to specify the properties of this state of matter in more detail to develop our idea; let us now turn to the dynamics of quarkonium production.It is well-known that the description of the data on heavy quarkonium production within the framework of perturbative QCD (pQCD) meets with siginificant difficulties. Bo...

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The production of in 200 GeV/nucleon oxygen-uranium interactions

Cited by 200 publications

References 9 publications

Colour deconfinement in nuclear collisions

Colour deconfinement in nuclear collisions

The Search for the Qgp: A Critical Appraisal

Quarkonium polarization in heavy ion collisions as a possible signature of the quark-gluon plasma

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