Improved Mesons Containing The Quark Mass Density Model And Its Applications

Because of the well-known difficulty of QCD in the nonperturbative domain,phe-nomenological models reflecting the characteristics of the strong interaction are widelyused in the study of hadrons,nuclear matter and quark matter。some part of them basedon quark and gluon degrees of freedom,and the others based on nucleon and meson,or quark and meson degrees of freedom。The quark mass density-dependent(QMDD) model is one of such candidates of ef-fective models.Although the QMDD model can provide a dynamical description ofconfinement and explain many other dynamical properties of strange quark matter,thismodel can not explain the abnormal expansion of stangelet and QCD deconfincmentdiagram,which relates of critical temperature vs.nuclear matter densityρ₂.In orderto overcome this difficulty,Zhang and Su suggested the quark mass density temper-ature dependent model (QMDTD) based on the ansatz that the bag constant dependson temperature。The QMDTD model has solved the difficulties mentioned above,andmade some application successfully。Meanwhile,quark meson coupling model(QMC)is also an effective model embodied the spirit of QCD theory,and have been employedto investigate the infinite nuclear matter and finite nuclei widely。However,QMDTD model and QMC model has some shortcomings,our study-ing motivation is tried to solve this shortcoming。We can summarized our works as:(1) We calculated the bag constant as a function of temperature strictly in IQMDDmodel。B(T) becomes an output,so that we consolidate the theoretical basis ofQMDTD model。(2)Based on the QMDD model,after introducing the coupling be-tween quarks and mesons,IQMDD model given up the boundary condition of MITbag model and can handle quark deconfinement phase transition and nuclear many-body problem in principle,which is the advantages of our model。(3)We applied thismodel to do many application of nuclear system,including neutron matter and strangehadronic matter。Some outcome manifested our model is successful。This paper is organized as follows:the first chapter is the introduction,it constitutethree parts:the brief introduction of QMDD model and QMDTD model including theirsuccess and shortcoings;QMC model including their success and shortcomings;the last section is devoted to summarize our works as well as the structure of the wholepaper。In the second chapter,an improved quark mass density- dependent model whichincludes the quark and non-linear scalar field coupling is presented。Numerical analy-sis of solutions of the new model is performed over a wide range of parameters。Thewave function of ground state quark and meson fieldσis given。Moreover,the root-mean squared charge radius,the magnetic moment,and the ratio between the axial-vector and the vectorβ-decay coupling constants of the nucleon are calculated。In the third chapter,inspired by the spirit of QMC model,an improved quark massdensity- dependent model which includes the couplings between quarks and non-linearscalarσmesons field andωmesons field is presented。We show that the present modelis successful to deseribe saturation properties,compressibility(K) and effective nuclearmass(M^*) of nuclear matter。The MIT bag boundary constrain has been given up inthis model and interactions between quarks and mesons are extended to the whole freespace。In the fourth chapter,by using the finite temperature quantum field theory,we cal-culate the effective potential of theσfield and extend improved quark mass density-dependent model to finite temperature。It is shown that this model can not only de-scribe the saturation properties of nuclear matter,but also can explain the quark decon-finement phase transition successfully。The critical temperature is given and effect ofωare addressed。In the fifth chapter,we extended IQMDD model to includeρmesons as well asσ,ωmesons.We investigate asymmetric nuclear matter using this model,especiallyfor neutron matter and neutron star matter。...