The two-photon-exchange(TPE)effect plays a key role in extracting the form factors(FFs)of the proton.In this work,we discuss several exact properties of the TPE effect in the elastic ep scattering.By taking four low e...The two-photon-exchange(TPE)effect plays a key role in extracting the form factors(FFs)of the proton.In this work,we discuss several exact properties of the TPE effect in the elastic ep scattering.By taking four low energy interactions as examples,we analyze kinematical singularities,asymptotic behaviors,and branch cuts of TPE amplitudes.The analytical expressions clearly indicate several exact relations between the dispersion relation(DR)and hadronic model(HM)methods.This suggests that the two methods must be modified to general forms,while novel forms yield the same results.After the modification,new DRs include a non-trivial term with two singularities.Furthermore,new DRs automatically include contributions due to the seagull interaction,meson-exchange effect,contact interactions,and off-shell effect.To analyze the elastic e^(±)}p scattering data sets,the new forms must be used.展开更多
Nucleon unpolarized structure functions in the ep elastic scattering are discussed. A new unpolarized structure function F^-3 due to the two-photon-exchange is given. Numerical results of the new structure function in...Nucleon unpolarized structure functions in the ep elastic scattering are discussed. A new unpolarized structure function F^-3 due to the two-photon-exchange is given. Numerical results of the new structure function in the limit of x →1 are displayed.展开更多
The effect of the two-photon exchange on the deuteron electromagnetic form factors is estimated based on an effective Lagrangian approach. A numerical estimate calculation of the effect is discussed. In particular, th...The effect of the two-photon exchange on the deuteron electromagnetic form factors is estimated based on an effective Lagrangian approach. A numerical estimate calculation of the effect is discussed. In particular, the effect on the polarization observables is analyzed.展开更多
基金Supported in part by the National Natural Science Foundation of China(11375044,11975075)。
文摘The two-photon-exchange(TPE)effect plays a key role in extracting the form factors(FFs)of the proton.In this work,we discuss several exact properties of the TPE effect in the elastic ep scattering.By taking four low energy interactions as examples,we analyze kinematical singularities,asymptotic behaviors,and branch cuts of TPE amplitudes.The analytical expressions clearly indicate several exact relations between the dispersion relation(DR)and hadronic model(HM)methods.This suggests that the two methods must be modified to general forms,while novel forms yield the same results.After the modification,new DRs include a non-trivial term with two singularities.Furthermore,new DRs automatically include contributions due to the seagull interaction,meson-exchange effect,contact interactions,and off-shell effect.To analyze the elastic e^(±)}p scattering data sets,the new forms must be used.
基金supported by National Natural Sciences Foundation under Grant Nos.10475088 and 10775148CAS under Grant No.KJCX3-SYW-N2
文摘Nucleon unpolarized structure functions in the ep elastic scattering are discussed. A new unpolarized structure function F^-3 due to the two-photon-exchange is given. Numerical results of the new structure function in the limit of x →1 are displayed.
基金Supported by National Natural Science Foundation of China (10775148,10975146)
文摘The effect of the two-photon exchange on the deuteron electromagnetic form factors is estimated based on an effective Lagrangian approach. A numerical estimate calculation of the effect is discussed. In particular, the effect on the polarization observables is analyzed.
