Transverse Momentum Spectra Of Jets Produced In High Energy Collisions

High energy heavy ions(nucleus-nucleus)collisions are an important means to study high energy nuclear physics.At present,the Relativistic Heavy Ion Collider(RHIC)and the Large Hadron Collider(LHC)are the large-scale laboratories in operation to study high energy nuclear physics.In the laboratory,heavy ions are accelerated and collided to create an extremely high temperature and density environment,which makes quarks overcome the confinement effect and separate from the nucleons.Quark-gluon plasma(QGP)produced in high energy heavy ion collisions is the only way to simulate the evolution of the universe.It is an important method to study the high energy collision process by analyzing the final state particles.Various jets are produced at the same time when QGP is produced in early nucleus-nucleus collisions.By analyzing the transverse momentum spectra of various jets,we can get some information about the participant quarks or partons in the early collisions.With the framework of the multi-source thermal model,we have analyzed the experimental transverse momentum spectra of various jets produced in different collisions at high energies.Two energy sources,a projectile participant quark and a target participant quark,are considered.Each energy source(each participant quark)is assumed to contribute to the transverse momentum distribution to be the TP-like function,i.e.a revised Tsallis–Paretotype function.The contribution of the two participant quarks to the transverse momentum distribution is then the convolution of two TP-like functions.We have used the TP like function and the convolution of two TP like functions to fit the experimental transverse momentum spectra measured by different collaborations.The related parameters such as the entropy index-related,effective temperature,and revised index are then obtained.The trends of these parameters are useful to understand the characteristic of high energy collisions.By comparing the parameters of the two methods,we can see that the fitting results of the two methods are consistent.By comparing the effective temperature parameters under different jet orders,it can be seen that the effective temperature decreases with the increase of jet order.This shows that the jet with high order corresponds to the source with less excitation degree.By comparing the effective temperature parameters of the leading jet and the second leading jet,it can be seen that the effective temperature from the leading jet spectrum is much larger than that from the second leading jet spectrum at the same energy,which is due to the leading jets are produced through more violent scattering.This is consistent with the change trend of effective temperature parameters in different jet orders.By comparing the effective temperature parameters under different centralities,it can be seen that the effective temperature increases slightly with the increase of centrality percentage,or the effective temperature are almost the same within the error range when the centrality percentage varies.The relation between the effective temperature and centrality percentage renders that QGP formed in central PbPb collisions has less influence on the jet transport.In addition,by comparing the effective temperature parameters of the jet produced by lepton and dilepton channels,it can be seen that the effective temperature parameters of the two channels are the same in the error range.This means that these jets have the common properties.