Experimental constraints on nonlinearities induced by two-photon effects in elastic and inelastic Rosenbluth separations

The effects of two-photon exchange corrections, suggested to explain the difference between measurements of the proton elastic electromagnetic form factors using the polarization transfer and Rosenbluth techniques, have been studied in elastic and inelastic scattering data. Such corrections could introduce \ensuremath{\varepsilon}-dependent nonlinearities in inelastic Rosenbluth separations, where \ensuremath{\varepsilon} is the virtual photon polarization parameter. It is concluded that such nonlinear effects are consistent with zero for elastic, resonance, and deep-inelastic scattering for all ${Q}^{2}$ and ${W}^{2}$ values measured.