Scattering of 50- to 140-Mev Photons by Protons and Deuterons

Further work below the meson threshold using both protons and deuterons as targets is reported. Experimental and theoretical cross sections for scattering of photons bv hydrogen are plotted as a function of lab energy at a c.m. angle of 90 deg . The conclusions are: (1) the observed scattering of photons by protons at 9O deg c.m. over the energy range 0 to 300 Mev is described well by a model of the proton as a Dirac particle plus strong pion interactions giving the well-known 3/2, 3/2/sup +/ and 1/2, 3/2-- resonances, provided the half life of the no meson is greater than 10/sup -18/ second; (2) the scattering of photons by deuteron; below meson threshold is more than expected. (A.C.)