We provide the important results from the proton0́3proton, proton0́3nucleus,nucleus0́3nucleus collision from the RHIC and LHC colliders, emphasizing jet-quenching in central collisions. We analyzed the behavior of nuclear modifi-cation factor and azimuthal anisotropies in dihadron correlations in variouscollisions at different beam energies. We analyzed the Inclusive transversemomentum spectra of charged particles in multiple detectors. The data fromfour of the RHIC detectors (STAR, PHENIX, PHOBOS, BRAHMS) and two of the LHC detectors (ALICE, CMS) are presented and compared forthe analysis. Initial conditions and final state effects of the high-energyheavy-ion collisions have been described. Both the RHIC and LHC data areconsistent with theoretical perturbative calculations incorporating the par-tonic energy loss in color-dense QCD matter, and this suggests formation ofa deconfined QGP phase in these high energy collisions.

Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 inverse microbarns. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cut-off used in this study (jet transverse momentum = 120 GeV/c) up to the statistical limit of the available data sample (jet transverse momentum approximately 210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet.

The production of jets in association with Z bosons, reconstructed via the mu+mu- and e+e- decay channels, is studied in pp and, for the first time, in PbPb collisions. Both data samples were collected by the CMS experiment at the LHC, at a center-of-mass energy of 5.02 TeV. The PbPb collisions were analyzed in the 0-30% centrality range. The back-to-back azimuthal alignment was studied in both pp and PbPb collisions for Z bosons with transverse momentum ptz> 60 GeV/c and a recoiling jet with ptj> 30 GeV/c. The pt imbalance, xjz= ptj/ptz, as well as the average number of jet partners per Z, rjz, were studied in intervals of ptz, in both pp and PbPb collisions. The rjz is found to be smaller in PbPb than in pp collisions, which suggests that in PbPb collisions a larger fraction of partons, associated with the Z bosons, lose energy and fall below the 30 GeV/c ptj threshold.

The kinematic correlations of isolated-[gamma]+jet scatterings in proton-proton and lead-lead collisions at centre-of-mass energy of 2.76TeV per nucleon pair are studied for the investigation of the jet quenching phenomena in hot and dense QCD medium. The analysis uses collision data delivered by the LHC and recorded by CMS detector at CERN. The angular correlation, the transverse momentum ratio and the rate of mono-photon events are measured and their dependence on the collisional impact parameter is examined in lead-lead collision. The results of proton-proton collisions are used as the reference to which the lead-lead results are compared. Significant energy loss of jets induced by the hot and dense medium, and its gradual rise in correlation to the size of the medium are observed in lead-lead collisions, while a modification of the direction of jet axis is not detected.

The aim of this study was to investigate the phenomenon of jet quenching due to the formation of the quark-gluon plasma in heavy ion and proton-proton collisions. This was done by comparing the transverse momentum, pT , ratio between a jet of hadronic particles, and a Z boson in both Monte Carlo simulations and real datasets, collected during the 2015 run of the Large Hadron Collider, using the Compact Muon Solenoid detector. The pT imbalance was studied in three di erent regions, namely for events where the Z boson had transverse momentum pT > 30GeV, pT > 60GeV and pT > 100GeV. The results show that there is a signi cant suppression of the jet pT in central heavy ion collisions compared to the proton-proton collisions, and the pT ratio decreases with higher initial pT.

Seven years after the first experiments in the new field of Nuclear Physics, the Highly Relativistic Heavy Ion Physics, the Nato-Advanced- Study-Institute on the 'Particle Production in Highly Excited Matter' was held from July 12 till July 24, 1992, at Il Ciocco, Castelvecchio Pascoli, near Lucca in Italy. The school took place at a mo ment when intensive efforts are mounted by the scientific community of Relativistic Heavy Ion Physics to meet the extraordinary challenge of the new upcoming physics opportunities. The gold beams of 10 GeV A at Brookhaven AGS have been sent to the experiments this Summer and we extent our congratulations to the persons and teams who made this possible. The Relativistic Heavy Ion Collider (RHIC) at Brookhaven is under construction and expected to allow experiments to see collisions in the intersec tion regions early 1998. The lead beams at the SPS at CERN scheduled for summer 1994 are eagerly awaited by 6 large experiments, and many scientists are planning the experiments at the planned LHC with heavy ions to be turned on before the year 2000. Seen against this background of rather fierce activity, we were most delighted when NATO accepted our application for an Advanced Study Institute oriented to the main subject of this young and dynamic field of research. We are very grateful to the Scientific Affairs Division of NATO and Dr. L. DaCunha, the director of the Advanced Study Institute program for giving our community this opportunity.