Methods for measurement of the proton form factors in processes with linearly polarized photons

In the Bethe-Heitler kinematics, we calculate the differential cross sections of the reactions ep→epγ and gγp→e+e-pγ for the case of linearly polarized photons. Effects of the proton form factors and recoil have been taken into account. The cross sections contain only squares of the electric and magnetic form factors of the proton. These cross sections are for measurement of compact form due to the use of a method for direct evaluation of matrix elements in the diagonal spin basis. Expressions for polarization asymmetries have been obtained. Measurements of these asymmetries in the reactions ep→epγ and γp→e+e-pγ could make it possible to find the ratio of squares of the Sachs electric and magnetic form factors of the proton. Such experiments are expected to be very important for obtaining new information on the behavior of these form factors and for resolving the disagreement in the results obtained within the Rosenbluth method and a method based on polarization transfer from the initial electron to the final proton. (authors)