Why is the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>J</mml:mi><mml:mo>/</mml:mo><mml:mi>ψ</mml:mi></mml:math>suppression enhanced at large transverse energy?

Capella, A.; Kaǐdalov, A. B.; Sousa, D.

doi:10.1103/physrevc.65.054908

Cited by 28 publications

(52 citation statements)

References 19 publications

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“…The latter sets in once a QGP starts forming, which, coupled with the rather strong QGP suppression, mimics the first drop at around E T ≃40 GeV. The overall good description of the NA50 data extends beyond E T > 100 GeV (not shown here) when incorporating transverse energy fluctuations [ 13] and a careful assessment of the minimum bias analysis [ 14], cf. ref.…”

Section: Spsmentioning

confidence: 99%

Two-component approach to J/ψ production in high-energy heavy-ion collisions

Grandchamp

Rapp

2003

Nuclear Physics A

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The production of charmonia in ultrarelativistic heavy-ion collisions is investigated including two sources. These are a primordial contribution coupled with various phases of dissociation, and a statistical coalescence of c andc quarks at the hadronization phase transition. Within a schematic fireball evolution, SPS data on J/Ψ production can be reasonably well reproduced. Remaining discrepancies in the Ψ ′ /Ψ ratio are discussed. Predictions for the J/Ψ centrality dependence at RHIC energies are confronted with first data from PHENIX. The pertinent excitation function of the N J/Ψ /N cc ratio exhibits a characteristic minimum structure signaling the transition from the standard J/Ψ suppression scenario (SPS) to predominantly statistical production (RHIC).

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Section: Spsmentioning

confidence: 99%

Two-component approach to J/ψ production in high-energy heavy-ion collisions

Grandchamp

Rapp

2003

Nuclear Physics A

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“…2 displays the ratio of J/ψ→µµ to Drell-Yan dimuons as a function of centrality. The agreement between model (solid line) and data is fair for semi-/central collisions (at E T >100 GeV, the data can be reproduced by accounting for transverse energy fluctuations and losses in the minimum bias analysis at impact parameters close to zero [32], cf. Ref.…”

mentioning

confidence: 93%

In-Medium Effects on Charmonium Production in Heavy-Ion Collisions

2004

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Charmonium production in heavy-ion collisions is investigated within a kinetic theory framework incorporating in-medium properties of open-and hidden-charm states in line with recent QCD lattice calculations. A continuously decreasing open-charm threshold across the phase boundary of hadronic and quark-gluon matter is found to have important implications for the equilibrium abundance of charmonium states. The survival of J/ψ resonance states above the transition temperature enables their recreation also in the Quark-Gluon Plasma. Including effects of chemical and thermal offequilibrium, we compare our model results to available experimental data at CERN-SPS and BNL-RHIC energies. In particular, earlier found discrepancies in the ψ ′ /ψ ratio can be resolved.The production systematics of heavy-quark bound states in (ultra-) relativistic collisions of heavy nuclei (A-A) is believed to encode valuable information on the hot and dense strong-interaction matter formed in these reactions [1]. Based on the notion that charm quark pairs (cc) are exclusively created in primordial (hard) nucleonnucleon (N -N ) collisions, it has been suggested [2] that a suppression of observed J/ψ mesons in sufficiently central and/or energetic A-A reactions signals the formation of a deconfined medium (Quark-Gluon Plasma=QGP), as tightly bound cc states are conceivably robust in hadronic matter. While theoretical [3] and (indirect) experimental evidence [4] supports N -N collision-scaling of total charm production, it has recently been realized [5,6,7] that coalescence of c andc quarks can induce significant regeneration of charmonium states in later stages of A-A collisions, especially if several pairs are present (e.g., N cc =10-20 in central Au-Au at RHIC). This is a direct consequence of (elastic) c-quark reinteractions, facilitating the backward direction of charmonium dissociation reactions, J/ψ + X 1 ⇋ X 2 + c +c (D +D).Recent lattice computations of Quantum Chromodynamics (QCD) have revealed important information on charm(onium) properties at finite temperature T , most notably: (i) an in-medium reduction of the open-charm threshold which is surprisingly continuous even across the phase transition region [8], and, (ii) the survival of J/ψ and η c states as resonances in the QGP phase [9,10], with essentially unmodified masses. Note that the use of charmonium spectral functions, in connection with appropriate asymptotic states, incorporates both (static) screening and (dynamical) dissociation mechanisms.In this letter, we propose an approach that implements charm properties inferred from lattice QCD as microscopic in-medium effects into a kinetic rate equation. It enables a comprehensive treatment of charmonium dissociation and regeneration across the phase transition, connecting hadronic and QGP phases in a continuous way, not present in previous calculations. E.g., in the kinetic approach of Ref.[6], J/ψ's were only considered in the QGP phase using their vacuum binding energy, whereas recent transport calculations [11,12] do n...

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“…absorption by comovers starts at t = t 0 and ends at t 1 , when the comover density n c ( b, s) · t 0 /t 1 has reached a value n f independent of b and s. The comover approach contains a definite time structure for anomalous suppression and we have not changed it. We also account for the transverse energy fluctuations [10], by replacing n c by Et <Et> n c , and the transverse energy loss [11] induced by the J/ψ trigger, by rescaling < E t > by a factor np−2 np , which have been shown to be significant for the explanation of the sharp decrease of S J/ψ (E t ) at E t > 100 GeV. In the choice of parameters we have followed [10,12]: n co ( b, s) = 1.5 n p ( b, s) with the participant density from eq.…”

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confidence: 99%

Time structure of anomalous J/ψ and ψ′ suppression in nuclear collisions

Hüfner

Zhuang

2003

Physics Letters B

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The data for the mean squared transverse momentum p 2 t (E t ) as function of transverse energy E t of J/ψ and ψ ′ produced in Pb-Pb collisions at the CERN-SPS are analyzed and it is claimed that they contain information about the time structure of anomalous suppression. A transport equation which describes transverse motion of J/ψ and ψ ′ in the absorptive medium is proposed and solved for a QGP and a comover scenario of suppression. While the comover approach accounts for the data fairly well without adjusting any parameter, the fit to the data within the QGP scenario requires to assume anomalous suppression to become effective rather late, 3−4 fm/c after the nuclear overlap.The discovery in 1996 of anomalous J/ψ suppression in Pb-Pb collisions at the SPS has been one of the highlights of the research with ultrarelativistic heavy ions at CERN [1]. Does it point to the discovery of the predicted quark gluon plasma (QGP)? Six years later the situation is still confused, since several models -with and without the assumption of a QGP -describe the observed suppression, after at least one parameter is adjusted. The data on the mean squared transverse momentum p 2 t (E t ) [2] for the ψ (this symbol stands for J/ψ and ψ ′ ) in the regime of anomalous suppression and as a function of transverse energy E t have received less attention -for no good reason. We claim: p 2 t (E t ) contains additional information about the nature of anomalous suppression and may help to distinguish between different scenarios. In this paper we investigate how the time structure of anomalous suppression influences the values p 2 t (E t ). This idea has already been considered more than 10 years ago [3] (c.f. also more recent works [4,5]) and is based on the following observation ( Fig.1): Anomalous suppression is not an instantaneous process, but takes a certain time depending on the mechanism. During this time ψ's produced with high transverse momenta may leak out of the parton/hadron plasma and escape suppression. As a consequence, low p t ψ's are absorbed preferentially and the p 2 t of the surviving (observed) ψ's show an increase δ p 2 t , which grows monotonically with the mean time t A , when anomalous absorption acts [5]. In this letter we propose a general formalism of how to incorporate the effect of leakage into the various models, which have been proposed to describe 1

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Why is theJ/ψsuppression enhanced at large transverse energy?

Cited by 28 publications

References 19 publications

Two-component approach to J/ψ production in high-energy heavy-ion collisions

Two-component approach to J/ψ production in high-energy heavy-ion collisions

In-Medium Effects on Charmonium Production in Heavy-Ion Collisions

Time structure of anomalous J/ψ and ψ′ suppression in nuclear collisions

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