On the Measurement of Sachs Form Factors in Processes without and with Proton Spin Flip

Abstract

The physical meaning of the decomposition of the Rosenbluth formula into two terms containing only squares of Sachs form factors has been established. A new method has been proposed for their independent measurement in the e p → e p elastic process when the initial proton at rest is fully polarized along the direction of motion of the final proton.

Reliability Analysis of the Results of the Known Experiments on Measuring of the Sachs Form Factor Ratio Using the Rosenbluth Technique. Polarization of the Final Proton in the $e \vec p \to e \vec p$ Elastic Process

“…The respective normalization uncertainties are 2.0 and 1. The method proposed in [19] for measuring squares of the SFFs in processes without and with proton spin flip requires a completely polarized proton target, which seems to be a matter for the quite distant future. As was noted above, in a wider sense it can be considered as a method based on polarization transfer from the initial to the final proton.…”

“…The method [19] is based on the expression for the differential cross section of process (3) in the LRF when the initial and final protons are polarized and have a common spin projection axis c (5)…”

“…Note that formula (7), like (1), can be decomposed into a sum of two terms involving only G 2 E and G 2 M . Averaging and summing (7) over polarizations of the initial and final protons, we obtain a different representation for cross section (1), designated as σ R [19]…”

“…which can be used for extracting R in the method of polarization transfer from the initial to the final proton [19,20].…”

“…In [19,20], a fourth method based on polarization transfer from the initial to the final proton was proposed, in which G 2 E and G 2 M can be extracted from direct measurements of the cross sections without and with proton spin flip in the elastic process e(p 1 ) + p (q 1 , s 1 ) → e(p 2 ) + p (q 2 , s 2 )…”