Medium-induced Photon Radiation And Dilepton Production From A Quark Jet In A Strongmagnetic Field

Since the beginning of this century,various high-energy heavy ion collision experiments have been carried out on the Large Hadron Collider(LHC)of the European Organization for Nuclear Research(CERN)and the Relativistic Heavy Ion Collider(RHIC)of the Brookhaven National Laboratory(BNL)of the United States.A large number of experimental results and theoretical analysis have shown that high temperature and high-density Quark-Gluon Plasma(QGP)is produced in the collision of heavy ions under the energy of LHC and RHIC.In high-energy heavy ion collisions,when the jet passes through the QGP medium,it will interact strongly with the strong interaction medium to induce gluon radiation,resulting in energy loss,that is,the jet quenching effect.In addition to gluons,multiple scattering can induce bremsstrahlung of real photons and virtual photons,among which virtual photons may also decay into dileptons.The photon signal and dilepton signal in heavy ion collisions can help us explore the generation mechanism of hot dense nuclear media,and photon radiation can also be compared with jet quenching caused by gluon radiation,so as to better study the properties of the two.In this paper,the G-W model is used to describe the interaction between the quark jet and the target partons with a static Yukawa potential to study the multiple scattering of the quark jet in the QGP medium,and the opacity expansion technique is used to simplify the calculation.Based on the study of photon bremsstrahlung,we further study the dileptonic generation caused by the decay of virtual photons.In addition,the relative motion of the two beams of High-energy charged particles during the collision of heavy ions will form a strong magnetic field perpendicular to the reaction plane,which in turn will affect the dynamics of the quark jet.In this paper,the corrected effective mass of quark is given by the fermion Landau Energy level under a constant magnetic field to calculate and analyze the photon and dilepton generation rate and the corresponding electromagnetic energy loss when the quark jet passes through the QGP under a strong magnetic field.This article first considers the case where the external magnetic field is zero.The calculation results show that the generation rate of photons decreases with the increase of the energy fraction,the electromagnetic energy loss increases with the increase of the energy of the jet,and the dileptons produce.The rate decreases as its own invariant mass increases.Then we studied the influence of the presence of a magnetic field on the above-mentioned physical quantities under different quark jet energies and different temperatures.Our calculation results show that the existence of a strong magnetic field has a depressing effect on the overall photon generation rate,and the depressing effect on the generation rate of high-energy photons is stronger.At a certain temperature,a strong magnetic field has a similar effect on the photon generation rate of quark jets of different energies.In the case of a given quark jet energy,the higher the temperature,the less obvious the reduction of the photon generation rate by the strong magnetic field.The overall reduction of the photon generation rate by the strong magnetic field also reduces the electromagnetic energy loss of the quark jet when it passes through the medium.On the other hand,the presence of a magnetic field also depresses the dilepton invariant mass spectrum to a certain extent,but the depressing effect for dileptons with smaller invariant masses is more pronounced than for dileptons with larger invariant masses.Obviously,this is because when the invariant mass of dileptons is large,the improvement of the mass of quarks by magnetic field correction is much smaller than the invariant mass of dileptons,so the magnetic field effect is relatively weak.In addition,at a certain temperature,a strong magnetic field has a stronger depressing effect on the dilepton generation rate of a quark jet with a smaller energy.In the case of a given quark jet energy,the higher the temperature,the less obvious the depressing effect of the strong magnetic field on the dilepton production rate.