SLAC -PUB-1042 (TH) and (EXP) EVALUATION OF THE J=O FIXED POLE IN NEUTRON COMPTON SCATTERING

We use the recent deuteron Compton data to evaluate the J=O fixed pole in neutron Compton scattering. This calculation includes the effects of both Glauber and Fermi motion corrections in the extraction of the free neutron cross section from the deuteron data, The result is consistent with the Born answer, zero.’ As a by-product, we show that the f:A2 ratio in Compton scattering is much larger than previously expected. (Submitted to Phys . Rev. ) * Work supported in part by the U. S. Atomic Energy Commission. TFellow of the University of Buenos Aires. Recently there has been a great deal of speculation concerning the existence and nature of fixed poles in two photon processes. Damashek and Gilman, and also Dominguez, Ferro-Fontan, and Suaya, ’ have established that a description of the high energy data of on-shell proton Compton scattering requires, in addition to the standard Regge terms, a constant real part whose magnitude and sign agrees, within errors with the Thomson limit