Photodisintegration of the deuteron in the few GeV region using asymptotic amplitudes

Exclusive photodisintegration of the deuteron in the 1–4 GeV range is described in terms of a simple covariant and gauge invariant approach using an effective counting rule as the hard part of the d–np vertex. At a scattering angle of θcm=90° a prescaling behavior of the differential cross section ∝s−(n−2) with n≈12 is obtained; going away from 90° the value of n decreases slowly, in qualitative agreement with the recent data.