Abstract
Charmonium states, such as the J/ψ and ψ(2S) mesons, are excellent probes of the deconfined state of matter, the Quark-Gluon Plasma (QGP) created in heavy ion collisions. In addition, the measurements in pPb collisions allow to study the cold nuclear matter effects, being crucial to disentangle these from the QGP-related effects in PbPb collisions. In this talk the new nuclear modification factor RAA of prompt and nonprompt J/ψ in PbPb collisions at [see formula in PDF] = 5.02 TeV were presented over a wide kinematic range (3 < pT < 50 GeV/c, |y| < 2.4), and fine event-centrality intervals. The results were compared to those at 2.76 TeV over a similar kinematic range. In addition, new prompt ψ(2S) RAA results at 5.02 TeV were reported. Finally the final prompt and nonprompt J/ψ results, as well as preliminary ψ(2S) results, in pPb collisions at 5.02 TeV, were discussed.
Highlights
Many phenomena, such as dissociation in the Quark-Gluon Plasma (QGP) and statistical recombination [1,2,3,4], on top of cold nuclear matter effects [5, 6], are required for a complete understanding of charmonium production in PbPb collisions
Measurements in pPb collisions are crucial for a quantitative determination of the QGP-related effects in PbPb collisions
The recombination mechanism in the QGP is only expected to affect charmonium production at low transverse momentum, while at high pT heavy quarkonium is likely to be produced by parton fragmentation, being sensitive to the parton energy loss in the QGP [7, 8]
Summary
Many phenomena, such as dissociation in the QGP and statistical recombination [1,2,3,4], on top of cold nuclear matter effects (modifications of nPDFs, initial-state energy loss and nuclear break-up) [5, 6], are required for a complete understanding of charmonium production in PbPb collisions. It is interesting to separate the prompt and nonprompt (from b hadron decays) charmonium components, since nonprompt charmonium should reflect medium effects on b hadron production, while the prompt component is affected by dissociation in the QGP and statistical recombination. In this talk, the PbPb data taken prompt and by the LHC nCoMnpSroemxppetrJim/ψenant datp√rosmNNpt=ψ(52.S02). The integrated luminosities were 28 pb−1, 34.6 nb−1 and 0.5 nb−1 for pp, pPb and PbPb data samples respectively
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
