J/ψ Suppression as a Signal for the Quark-Gluon Plasma
نویسنده
چکیده
We review the search for the quark-gluon plasma using the signal of the suppression of J/ψ production in high-energy heavy-ion collisions. Recent anomalous J/ψ suppression in high-energy Pb-Pb collisions observed by the NA50 Collaboration are examined and compared with earlier results from pA and nucleus-nucleus collisions with heavy ions of smaller mass numbers. 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 number of nucleon-nucleon collisions at a spatial point exceeds about 4 and corresponds to a local energy density of about 3.4 GeV/fm.
منابع مشابه
Quarkonium Polarization in Non-relativistic QCD and the Quark-Gluon Plasma
We examine angular distributions of leptons arising from the decay of J/ψ in inclusive hadroproduction. Taking into account feed-down contributions from χ1,2, a flat distribution emerges without fine tuning parameters. Changes in the ratio of direct to total J/ψ cross sections would change this distribution significantly. Such angular distributions are, therefore, confirmatory tests of the J/ψ ...
متن کاملJ/Ψ suppressions in a thermally equilibrating quark-gluon plasma at RHIC
We estimate the survival probability of J/ψ in relativistic heavy-ion collisions, using both short-distance QCD and nuclear absorption mechanism. The suppression is found to be almost 100 percent for a thermally equilibrating quark-gluon plasma. The measurement of such a huge suppression of J/ψ may suggest the existence of a deconfined partonic medium, possibly a thermalised quark-gluon plasma,...
متن کاملTheoretical Issues in J/ψ Suppression
Two decades ago Matsui and Satz suggested that Debye screening in the quark-gluon plasma would result in J/ψ suppression in heavy ion collisions. Much has happened in the subsequent years, and the picture of quark-gluon plasma at present is rapidly evolving – what does it imply for the J/ψ suppression? What are the recent RHIC and SPS results trying to tell us? What else has to be done? This ta...
متن کاملJ/ψ Suppression in Pb+Pb Collisions: A New Look at Hadrons vs. Plasma
A reexamination of hadronic comover scattering indicates that this mechanism cannot explain the observed J/ψ suppression in Pb+Pb interactions. The possibility of quark-gluon plasma formation is then plausible. We present calculations in which the χc and ψ ′ are suppressed by the plasma while the J/ψ itself is not.
متن کاملJ/ψ and Ψ Suppression in Hadronic Matter
We present a microscopic calculation of the breakup cross sections of J/ψ and ψ on pions and nucleons as a function of the kinetic energy. These cross sections are used for the investigation of the J/ψ to continuum and ψ/J/ψ ratios in ultrarelativistic heavy ion collisions. The contribution of produced comoving pions to the ψ/J/ψ signal is calculated. While this model can account for the data, ...
متن کامل