Measurement of the reaction /sup 4/He(. gamma. ,. pi. /sup 0/) /sup 4/He for E/sub. gamma. / = 290 MeV

We report measurements of differential cross sections for the reaction /sup 4/He(..gamma..,..pi../sup 0/) /sup 4/He with a photon energy of 290 MeV. Use of a good-resolution ..pi../sup 0/ spectrometer allowed restriction of events to those where the residual /sup 4/He nucleus was left in the ground state (the coherent process). By detecting the ..pi../sup 0/ directly, we thus provide the first forward-angle data for this reaction in the ..delta..-resonance region. Our results are in good agreement with a recent ..delta..-hole model calculation.