Relativistic treatment of bremsstrahlung in the process pp → ppγ with allowance for isobar channels and possibility of discriminating between different types of nucleon-nucleon interaction

Abstract

A relativistic quasipotential formalism for describing electromagnetic processes involving nucleons that takes into account an explicit coupling to the NΔ (1232 MeV) and NN* (1440 MeV) channels is developed. On one hand, this formalism is a relativistic generalization of the Lomon-Ray approach to describing nucleon-nucleon scattering within a framework explicitly including isobar degrees of freedom; on the other hand, it relies on the formalism developed by Lev [F.M. Lev, hep-ph/9403222] within relativistic quantum mechanics for constructing the electromagnetic-current operator for interacting particles. The formalism makes it possible to obtain a consistent description of a two-nucleon system in the energy region extending up to 1 GeV. It is applied to describing the reaction pp → ppγ over a kinematical region in which corrections associated with a virtual delta isobar are of importance. The sensitivity of this reaction to the type of the short-range component of the nucleon-nucleon potential and the possibility of discriminating between the Moscow potential and meson-exchange potentials on the basis of experimental data are confirmed.