Modiication of the Equivalent Photon Approximation (epa) For`resolved ' Photon Processes. 1

We propose a modiication of the equivalent photon approximation (EPA) for processes which involve the parton content of the photon, to take into account the suppression of the photonic parton uxes due to the virtuality of the photon. We present simple, physically motivated anss atze to model this suppression and show that even though the parton content of the electron no longer factorizes into an electron ux function and photon structure function, it is still possible to express it as a single integral. We also show that for the TRISTAN experiments its eeect can be numerically of the same size as that of the NLO corrections. Further, we discuss a possible measurement at HERA, which can provide an experimental handle on the eeect we model through our anss atze.