Changes

It is convenient to adopt the Gottfried Jackson frame. In particular, we boost into the reference frame of the produced resonance and orient the coordinate system such that the photon is in the +z direction and the x-axis is co-planar to the recoiling proton, thus defining xz as the production plane. A consequence of this choice is that <math>m=\lambda_\gamma-\lambda_R</math>

It is convenient to adopt the Gottfried Jackson frame. In particular, we boost into the reference frame of the produced resonance and orient the coordinate system such that the photon is in the +z direction and the x-axis is co-planar to the recoiling proton, thus defining xz as the production plane. A consequence of this choice is that <math>m=\lambda_\gamma-\lambda_R</math>

To project the photon polarization state onto the production plane, we relate the linear polarization bases in the laboratory and production coordinate systems:

To express the initial photon linear polarization state in the reflectivity basis, we relate the linear polarization bases in the laboratory and Gottfried-Jackson coordinate systems:

:<math>\left(\begin{array}{c}x_\mathrm{lab} \\ y_\mathrm{lab}\end{array}\right)=

:<math>\left(\begin{array}{c}x_\mathrm{lab} \\ y_\mathrm{lab}\end{array}\right)=