Possible Method for Measuring the Proton Form Factors in Processes with and without Proton Spin Flip

Abstract

The ratio of the squares of the electric and magnetic proton form factors is shown to be proportional to the ratio of the cross sections for the elastic scattering of an unpolarized electron on a partially polarized proton with and without proton spin flip. The initial proton at rest should be polarized along the direction of the motion of the final proton. Similar results are valid for both radiative $ep$ scattering and the photoproduction of pairs on a proton in the Bethe--Heitler kinematics. When the initial proton is fully polarized in the direction of the motion of the final proton, the cross section for the $ep\to ep$ process, as well as for the $ep\to ep\gamma$ and $\gamma p\to e\bar{e}p$ processes, without (with) proton spin flip is expressed only in terms of the square of the electric (magnetic) proton form factor. Such an experiment on the measurement of the cross sections without and with proton spin flip would make it possible to acquire new independent data on the behavior of $G_E^2(Q^2)$ and $G_M^2(Q^2)$, which are necessary for resolving the contradictions appearing after the experiment of the JLab collaboration on the measurement of the proton form factors with the method of polarization transfer from the initial electron to the final proton.

7 pages, revtex4

References in corpus (1)

• The ratio of proton's electric to magnetic form factors measured by polarization transfer

Cited by in corpus (4)

• Alternative way to understand the unexpected results of the JLab polarization experiments to measure the Sachs form factors ratio
• On the physical meaning of Sachs form factors and on the violation of the dipole dependence of G_E and G_M on Q^2
• On the Measurement of Sachs Form Factors in Processes without and with Proton Spin Flip
• Angular Dependence of the Polarization Transfer to the Proton in the $e\vec{p}\to e\vec{p}$ Process