And Ψ′ Suppression in High-Energy Heavy-Ion Collisions (original) (raw)

Signatures of absorption mechanisms for and ψ′ production in high-energy heavy-ion collisions

Nuclear Physics A, 1998

Oak Ridge, TN 37831 J/ψ and ψ ′ produced in high-energy heavy-ion collisions are absorbed by their collisions with nucleons and produced soft particles, leading to two distinct absorption mechanisms. The signature of absorption by produced soft particles, as revealed by ψ ′ production data, consists of a gap and a change of the slope in going from the pA line to the nucleus-nucleus line when we make a semi-log plot of the survival probability as a function of the path length. Using this signature, we find from the J/ψ production data in pA, O-Cu, O-U, and S-U collisions that the degree of J/ψ absorption by produced soft particles is small and cannot account for the J/ψ data in Pb-Pb collisions. The anomalous suppression of J/ψ production in Pb-Pb collisions can be explained as due to the occurrence of a new phase of strong J/ψ absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm 3 . To probe the chemical content of the new phase, we propose to study the abundance of open-charm mesons and charm hyperons which depends sensitively on the quark chemical potential.

Drell-Yan Cross Section and J/psi Production in High-Energy Nucleus-Nucleus Collisions

arXiv:hep-ph/9809497v2 6 Oct 1998 O R N L-C T P-9805 and hep-ph/9809497 D rell-Y an C ross Section and J= P roduction in H igh-E nergy N ucleus-N ucleus C ollisions C heuk-Y i n W ong Physics D ivision,O ak R idge N ationalLaboratory, O ak R idge,T N 37831,U SA E-m ail : wongc@ ornl .gov W e use the D rell-Y an di erentialdistribution dN A B D Y =dE T in high-energy nucleusnucleus collisions to obtain a relation betw een the transverse energy E T and the im pact param eter b. Such a relation is then utilized to study the transverse-energy dependence ofJ= production in P b-P b collisions,using the J= absorption m odel presented previously. T he anom alous P b-P b suppression data at 158A G eV can be explained ifone assum es the occurrence ofa new phase of strong J= absorption w hen the energy density exceeds 4.2 G eV /fm 3 . T he results are extended to m ake predictions for J= production at higher collision energies. It is found that J= survival probabilities reach the low est survival lim it w hen the nucleon-nucleon center-of-m ass energies p s is greater than about 35 G eV .

Absorption in Heavy-Ion Collisions

Nuclear Physics A, 2004

We present a new calculation of the π-J/ψ dissociation cross sections within the Constituent Quark-Meson Model recently introduced. To discuss the absorption of J/ψ in heavy-ion collisions, we assume the J/ψ to be produced inside a thermalized pion gas, as discussed by Bjorken, and introduce the corrections due to absorption by nuclear matter as well. We fit the absorption length of the J/ψ to the data obtained at the CERN SPS by the NA50 Collaboration for Pb-Pb collisions. Collisions of lower centrality allow us to determine the temperature and the energy density of the pion gas. For both these quantities we find values close to those indicated by lattice gauge calculations for the transition to a quark-gluon plasma. A simple extrapolation to more central collisions, which takes into account the increase of the energy deposited due to the increased nucleon flux, fails to reproduce the break in J/ψ absorption indicated by NA50, thus lending support to the idea that an unconfined quark-gluon phase may have been produced. This conclusion could be sharpened by analysing in a similar way, as a function of centrality, other observables such as strange particle production.

Suppression of ψ′ and J/ψ in High-Energy Heavy-Ion Collisions

Physical Review Letters, 1996

The experimental ratio of ψ ′ to J/ψ is approximately a constant in pA collisions, but decreases as the transverse energy increases in nucleus-nucleus collisions. These peculiar features can be explained as arising from approximately the same cc-baryon absorption cross section for ψ ′ and J/ψ but greater disruption probabilities for ψ ′ than for J/ψ due to the interaction of the cc system with soft particles produced in baryon-baryon collisions.

J/ψ Suppression at Forward Rapidity in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

Physical Review Letters, 2012

The ALICE experiment has measured the inclusive J/ψ production in Pb-Pb collisions at √ s NN = 2.76 TeV down to zero transverse momentum in the rapidity range 2.5 < y < 4. A suppression of the inclusive J/ψ yield in Pb-Pb is observed with respect to the one measured in pp collisions scaled by the number of binary nucleon-nucleon collisions. The nuclear modification factor, integrated over the 0%-80% most central collisions, is 0.545 ± 0.032(stat.) ± 0.083(syst.) and does not exhibit a significant dependence on the collision centrality. These features appear significantly different from measurements at lower collision energies. Models including J/ψ production from charm quarks in a deconfined partonic phase can describe our data. * See Appendix A for the list of collaboration members J/ψ suppression at forward rapidity in Pb-Pb collisions at √ s NN = 2.76 TeV ALICE Collaboration

Psi' and J/Psi Suppression in High-Energy Nucleon-Nucleus and Nucleus-Nucleus Collisions

The observed features of ψ ′ to J/ψ suppression in pA and nucleusnucleus collisions can be explained in terms of a two-component absorption model. For the hard component of the absorption due to the interaction of the produced cc systems with baryons at high relative energies, the absorption cross sections are insensitive to the radii of the cc systems, as described by the Additive Quark Model. For the soft component due to the low energy cc interactions with soft particles produced by other baryon-baryon collisions, the absorption cross sections are greater for ψ ′ than for J/ψ, because the breakup threshold for ψ ′ is much smaller than for ψ.

Suppression of {psi}{prime} and {ital J}/{psi} in high-energy heavy-ion collisions

Physical Review Letters

The experimental ratio of ψ ′ to J/ψ is approximately a constant in pA collisions, but decreases as the transverse energy increases in nucleus-nucleus collisions. These peculiar features can be explained as arising from approximately the same cc-baryon absorption cross section for ψ ′ and J/ψ but greater disruption probabilities for ψ ′ than for J/ψ due to the interaction of the cc system with soft particles produced in baryon-baryon collisions.