Study Of Measuring The Electro-Weak Form Factors Of Proton Directly Via Electron-Proton Scattering

The ratio of the proton elastic electromagnetic form factors, G_E/G_M, was obtained by measuring P_t and P_l, the transverse and longitudinal recoil proton polarization components of the elastic scattering process (e|→)p → e(p|→) at low transverse momentum Q², respectively. When we measure the differential cross section of the scattering process, the contribution of the single-photon exchange process is the main part, and the contribution of the weak interaction process is much less important than the electromagnetic interaction process. Finally we can get the ratio of the form factors G_E/G_M is directly proportional to P_t/P_l. When the square of the transverse momentum Q² is big enough, such as the energy of the incoming electron E₁ = 100GeV, the contribution of the weak interaction process is not negative any more, it will be necessary to consider the contribution of the weak interaction between the electron and the proton. Under such a consideration, we have to introduce four new weak form factors: two vector current form factors, H₁ and H₂ (or saying H_E and H_M), two axial-vector current form factors, H₃ and H₄. In this paper, we will consider all the necessary polarizations of the initial incoming electron and the final recoil proton of the elastic scattering process ep → ep, and find out the relationship between the differential cross sections and the six form factors which have been defined before. At last we express the ratios of the form factors H_E/G_M, H_M/G_M and H₃/G_M, by the differential cross sections.