The Mass Shifts Of Charmonium At Finite Temperature In External Magnetic Fields By Applying QCD Sum Rules

In this article,we mainly use QCDSR to study the mass displacement of charmonium ηc and J/ψ under the condition of the outer magnetic fields,finally got the main reasons and sub-main reasons of impacting mass shifts.The first chapter introduces the effective theory of hadron for the analysis of charmonium mass shifts.The second chapter introduces QCDSR,QCDSR for heavy quarks,and the calculation of charmonium mass,gives a general results in ordinary vacuum under the condition of no external magnetic field.The third chapter,charmonium is calculated by using the QCDSR with the external magnetic field,and give its mass displacement and its analysis.The fourth chapter,The mass shifts of charmonnium is calculated by using QCDSR in finite temperature with the external magnetic field,found with the increase of temperature,the mass of charmonnium will become small.First of all,with the external magnetic field conditions,the operator product expansion and spectral density hypothesis need to reconsider.In addition to the perturbation effect,the effect of perturbation of heavy quarks graph is a sub-main origin of mass shifts that cannot be ignored.We investigated effects of strong magnetic fields on the mass spectra of S-wave charmonium states,namely ηc and J/ψ,and elaborated the ansatz for the spectral density in the QCD sum rule method,the so-called phenomenological side,to consistently manipulate mixing effects in external magnetic fields.We implemented quadratic terms in the order of magnetic fields for the spectral ansatz and discussed a role of each term on the basis of a partial fraction decomposition(3.9)and numerical analyses.with an appropriate form of the spectral ansatz obtained in the present work,we found that the mass shifts of static ηc and the longitudinal J/ψprecisely agree with those obtained from an effective Lagrangian approach,indicating that the dominate effect of magnetic fields comes from a level repulsion between those two states.As for the transverse J/ψ,we obtained an increasing magnitude of a magnetic field,while the transverse J/ψ is not mixed with any state.This behavior of the transverse J/ψ and residual mass shifts of ηc and the longitudinal J/ψ imply existense of some other effects not fully described by the mixing effect in leading-order effective Lagrangian in mesonic degrees freedom.We examined effects of a mixing effect with higher states and continuum.This was carried out by approximating the intermediate states as a perturbative heavy-quark loop with two insertions of external magnetic fields.We found that this effect gives rise to a splitting between the longitudinal and transverse J/ψ and indeed an increasing mass of the transverse J/ψ.When both the external magnetic field and finite temperature are considered,the influence of the temperature be put in the gluon condensate.In terms of phenomenlogical,spectral density hypothesis does not need to change,but the operator expansion aspect is need to be change due to temperature,the additional items caused by temperature need be added.Will the modified operator production expansion substitute into the main equation,we found:as temperature rise,the gluon condensate decrease,and the mass of charmonium also become smaller.