On the mesonic-exchange currents in the photomesic reactions

The γd → πsup(o)d reaction is analysed in the framework of the relativistic many-body theory with mesonic degrees of freedom explicitly present. It is shown that the mesonic correlations can be grouped into transition operators containing vertices of some elementary reactions between photons, nucleons and pions. The wavefunction corrections due to meson-exchange currents are included in the transition operators and the S matrix is obtained with the non-relativistic deuteron wavefunction. (author)