Neutron-proton bremsstrahlung results at 200 MeV

Abstract

Neutron-proton bremsstrahlung cross sections $\frac{d\ensuremath{\sigma}}{d{\ensuremath{\Omega}}_{p}d{\ensuremath{\Omega}}_{n}}$ and asymmetries at ${E}_{\mathrm{lab}}=200$ MeV have been calculated using the Lomon-Feshbach and Hamada-Johnston models. The cross sections from these models differ by about 10% at ${\ensuremath{\theta}}_{p}={\ensuremath{\theta}}_{n}=30\ifmmode^\circ\else\textdegree\fi{}$ after approximate adjustments are made for elastic scattering differences. The cross sections integrated over only the larger peak in the ${\ensuremath{\theta}}_{\ensuremath{\gamma}}$ distribution differ by about 16%. The calculations are based on an expansion of the electromagnetic current in powers of the photon energy rather than an expansion of the complete bremsstrahlung matrix element. The calculation includes the external emission amplitude to all orders in the photon energy and the electric dipole part of the internal emission amplitude. Higher order contributions to the internal emission amplitude are discussed. The numerical results and amplitude expressions are compared with those of other authors. We find numerical agreement with Brown and Franklin but not with Celenza, Gibson, Liou, and Sobel.NUCLEAR REACTIONS $\mathrm{NN}$ bremsstrahlung amplitudes, nonlocal and exchange effects; $\mathrm{np}$ bremsstrahlung $\frac{d\ensuremath{\sigma}}{d{\ensuremath{\Omega}}_{p}d{\ensuremath{\Omega}}_{n}}$ and asymmetry calculated at ${E}_{\mathrm{lab}}=200$ MeV with Lomon-Feshbach and Hamada-Johnston models.