Resonances contribution to two-photon exchange effects and possible large forward–backward asymmetry in image

The resonances (image) contribution to two-photon exchange (TPE) effects in image is calculated in a simple hadronic model. The calculation shows the TPE contributions by resonance image, which are dependent on the unknown phases image of protonʼs time-like form factors image, are much larger than the TPE contributions by non-resonance and are comparable with measurement precision of coming PANDA detector at image for most image.