Analysis Of Elastic ?-N Scattering By Heavy Baryon Chiral Perturbation Theory

The chiral perturbation theory(ChPT)is an effective field theory for quantum chro-modynamics(QCD)in the low-energy field.Once the chiral perturbation theory involves the baryons,there will be a problem of power counting breaking(PCB).Three correction schemes are given for the problem,namely:Heavy B ary on(HB),Infrared Regularization(IR)and Extended-On-Mass-Shell(EOMS).In this paper,Heavy Baryon Chiral pertur-bation theory(HBXPT)is used to calculate the scattering amplitude of the elastic ?-N scattering in the S U(2)v and S U(3)v groups to the third order,where the third-order scat-tering amplitude contribution only contains loop diagrams in the SU(3)v groups.Based on this,relevant data analysis of elastic ?-N scattering was performed.Firstly,in the S U(2)v group,we keeping the lnm/? term and absorbing the lnm/? term to determine the low energy constant in the effective Lagrangian,and then use the two sets of low energy con-stants to fit the partial-wave phase shift.As a result,the low energy constant obtained by retaining the lnm/? term in the scattering amplitude can better describe the partial-wave phase shift.Secondly in the S U(3)y group,the Inm/? term of the scattering amplitude is p-reserved to obtain the low energy constant to fit the partial-wave phase shift and compare it with the results in the S U(2)v group.The results show that the theoretical calculation of the partial-wave phase shift is more consistent with experimental data in the S U(2)v group.Finally,the paper discussed convergence problem in the S U(2)v group and calcu-lated the S-wave scattering length of the elastic ?-N scattering.