Investigation Of The Redistribution Of Lost Energy From Jets With AMPT Model

High energy collisions of heavy ions are expected to create a new form of matter—quark-gluon plasma (QGP) which consists of deconfined and chirally-symmetric quarks and gluons under extreme temperature and density conditions. Partons produced from early stage collisions of beam quarks and gluons interact with the medium and lose energy when they propagate through the hot and dense medium. This parton energy loss is usually called jet quenching and sensitive to the properties of the QGP medium so it is an useful tool for study the QGP.Ultra-relativistic heavy-ion collisions have been performed at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory and the Large Hadron Collider(LHC) at Eurpean Organization for Nuclear Research(CERN) since 2003. Many experiment results and theoretical calculations demonstrated that QGP has been formed at RHIC and LHC. Recently,CMS collaboration at LHC has measured the asymmetry of the transverse momentum of two correlated full constructed jets in PbPb collision. Further detailed studies show that this phenomenon is due to particles from sub-leading jet being scattered out of the jet cone. The event which dijet asymmetry is larger compared with the balanced one has a modified transverse momentum distributions. These observations indicated that subleading jets inter-act with the medium and experience a larger amount of energy loss. Hard partons may loss energy via elastic and inelastic collisions with the constituents of the QGP medium. In various parton energy loss formalisms there are main approximation that is the collinear or small-angle radiation approximation which assumes that the transverse momentum of the radiated gluon is much smaller than its energy. But angel between final states partons after 2â†'2 elastic collisions and primary hard par-tons can be lager. So collision energy loss may have a sizeable contribution to the dijet asymmetry and momentum redistribution.Within a multiple transport (AMPT) model, we study the momentum imbal-ance of dijet events and redistribution of the lost energy from jet cone for PbPb collisions at the LHC and the AMPT model calculation can qualitatively describe the CMS results.Further detailed studies show that the redistribution of the lost energy are mainly developed in partonic phase and fragmentation and hadronic in-teraction contributed little. Finally we found there are lots of small pt particles have an large angel with dijets. Since only elastic collisions are included within AMPT model, the description of CMS data using AMPT model implies the important role played by the elastic collisions between the jet partons with the medium partons in explaining the redistribution of lost energy from the jet cone.