ar X iv : h ep - p h / 02 10 01 0 v 1 1 O ct 2 00 2 Jet quenching in heavy ion collisions at LHC 1

We discuss the potential information about highly excited QCD-matter provided by medium-induced partonic energy loss, known as " jet quenching ". In particular, with its large acceptance hadronic and electromagnetic calorimetry, the Compact Muon Solenoid detector at LHC collider is a promising device to study these effects. We present physics simulations of observables such as the jet distribution with impact parameter, the azimuthal anisotropy of jet quenching, and the effects of b-quark energy loss on the high-mass dimuon continuum and secondary J/ψ production. 1 Hard probes at LHC with CMS detector High-p T QCD phenomena are perspective tools to study the properties of the hot matter created in ultrarela-tivistic nuclear interactions [1]. Hard probes such as quarkonia, hard jets and heavy quarks are not thermalized but carry information about the earliest stages of a system subject to numerous final-state effects in heavy ion collisions at SPS and RHIC. At the LHC, a new regime is reached where hard and semi-hard QCD multi-particle production can already dominate over underlying soft events. The following signals of jet quenching due to medium-induced parton energy loss [2] can be identified as being observable in heavy ion collisions at LHC [1]. 1) The suppression of high-p T jet pairs as compared to what is expected from independent nucleon-nucleon interactions pattern [3]. It includes modification of jet impact parameter dependence [4] and azimuthal anisotropy of jet quenching in non-central collisions [5]. 2) The p T-imbalance in γ+jet [6] and Z(→ µ + µ −)+jet [7] channels. 3) The suppression of high-p T hadron and photon (leading particle) yields due to a modification of the jet fragmentation function [8]. 4) The modification of the high mass dimuon spectra from semileptonic B and D meson decays and secondary charmonium production due to heavy quark energy loss [9, 10]. All above signals can be studied in CMS Heavy Ion Programme [11]. The Compact Muon Solenoid (CMS) is a general purpose detector designed primary to search for the Higgs boson in proton-proton collisions at LHC [12]. Accordingly, the detector is optimized for accurate measurements of the characteristics of high-energy leptons, photons and hadronic jets in a large acceptance, providing unique capabilities for " hard probes " for both pp and AA collisions. The central element of CMS is the magnet, a 13 m long and 6 m diameter solenoid with an internal radius ≈ 3 m, which will provide a …