Suppression

Relativistic Nucleus-Nucleus Collisions and the QCD Matter Phase Diagram

“…In addition to high T breakup of cc or J/ , we have to take account of the so-called "normal suppression" of charmonium yields, observed in proton-nucleus collisions [233]. This effect is due to a re-scattering dissociation of the primordially produced, pre-hadronic cc system upon traversal of (cold) hadronic matter [234]. It can be studied in p+A collisions where the data on J/ production relative to pp collisions can be described by the survival probability…”

Production of the charmonium statesχc1andχc2in proton nucleus interactions atAbt1, Adams2, Agari3 et al. 2009Phys. Rev. D270130View full textAdd to dashboardCite

“…In this respect, the measurement of the fraction of J=c arising from feeddown decays ( c and c ð2SÞ) is important, since the anomalous suppression is expected to be sensitive to the mass and binding energy of the different charmonium states. Directly produced J=c survive in the quark-gluon plasma up to about 1:5T c [28], T c being the critical temperature, while c and c ð2SÞ states dissociate just above T c . Thus, several drops in the distribution of charmonium survival probability as a function of the temperature are expected, with the size of the drops dependent on the fractions R c and R c ð2SÞ (R c ð2SÞ ¼ ðc ð2SÞÞBrðc ð2SÞ!J=c XÞ ðJ=c Þ ).…”

“…They generally assume R c $ 0:3 and R c ð2SÞ $ 0:1. Nevertheless, all the proposed models fail to simultaneously describe all the existing data, as they all overestimate the suppression unless other effects, such as J=c regeneration, are assumed to describe the RHIC data [28]. From the value of R c shown in Sec.…”

7 Relativistic Nucleus-Nucleus Collisions and the QCD Matter Phase Diagram

“…This effect is due to a re-scattering dissociation of the primordially produced, pre-hadronic cc system upon traversal of (cold) hadronic matter [234]. It can be studied in p+A collisions where the data on J/Ψ production relative to pp collisions can be described by the survival probability…”

“…A different aspect of charmonium production in A+A collisions requires attention: at the stage of universal hadronization a certain fraction of bound cc mesons results, as the outcome of the density of uncorrelated c and c quarks in the QGP medium as it enters hadronization [240,241]. The stage of statistical hadronization (recall chapter 3) is omitted in the charmonium suppression models [41,230,234,235], which proceed in two steps (only): primordial nucleon-nucleon collisions produce an initial input of cc pairs, proportional to σ N N cc × N AA coll (b). In vacuum, the low relative momentum fraction of these cc pairs (about 1%) would evolve into charmonium hadrons, after a formation time of several f m/c.…”