Δ(1232)-nucleon interaction in the2H(p,n)charge-exchange reaction

Abstract

The ${}^{2}\mathrm{H}(p,n)$ charge exchange reaction at ${T}_{p}=790\mathrm{MeV}$ is used to study the \ensuremath{\Delta}(1232)-nucleon $(\ensuremath{\Delta}N)$ interaction in the \ensuremath{\Delta} resonance excitation energy region. For the $\ensuremath{\Delta}N$ potential, a meson exchange model is adopted where \ensuremath{\pi}, \ensuremath{\rho}, \ensuremath{\omega}, and \ensuremath{\sigma} meson exchanges are taken into account. The deuteron disintegration below and above pion threshold is calculated using a coupled-channel approach. Various observables, such as the inclusive cross section, the quasifree \ensuremath{\Delta} decay, the coherent pion production, and the two-nucleon breakup, are considered. It is shown that these observables are influenced by the dynamical treatment of the \ensuremath{\Delta} degrees of freedom. Of special interest is the coherent pion decay of the \ensuremath{\Delta} resonance, which is studied by means of the exclusive reaction ${}^{2}\mathrm{H}(p,n{\ensuremath{\pi}}^{+}{)}^{2}\mathrm{H}.$ Both the peak energy and the magnitude of the coherent pion production cross section depend very sensitively on the strength of the $\ensuremath{\Delta}N$ potential. The coherent pions have a peak energy of $\ensuremath{\omega}=300\mathrm{MeV}$ and a strongly forward peaked angular distribution.