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The deuteron spectrum in n+p -> 2 H(pi pi) at k_n = 1.88 GeV/c and theta_d = 0^o is explained by considering a Delta Delta excitation as the dominant reaction mechanism for the 2 pi production. We present a new theoretical approach based on a coupled channel formalism which allows to include the residual interaction within the intermediate Delta Delta and Delta N systems. The corresponding interaction potentials V_{DeltaDelta} and V_{DeltaN} are adopted from a meson exchange model with pi, rho, omega, and sigma exchange taken into account. The influence of the residual interaction on the deuteron spectrum is studied. We also predict the angular distribution of the two pions. It is shown that this distribution is closely connected to the spin structure of the DeltaDelta excitation., Comment: RevTeX, 22 pages, 11 figures, uses epsfig macro

The deuteron spectrum in n+p -> d+pi+pi at k_n = 1.88 GeV/c and theta_d = 0 deg is explained by considering a Delta-Delta excitation as the reaction mechanism for the 2pi production. We study the influence of intermediate Delta-Delta and Delta-Nucleon interactions on the spectrum. The angular distribution of the pions is predicted., Comment: Contribution to Baryons'98 Conference, Bonn, Sept 22-26, 1998

The 2H(p,n) charge exchange reaction at T_p=790 MeV is used to study the Delta(1232)-nucleon interaction in the Delta resonance excitation energy region. For the Delta-N potential, a meson exchange model is adopted where pi, rho, omega, and 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 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 Delta degrees of freedom. Of special interest is the coherent pion decay of the Delta resonance which is studied by means of the exclusive reaction 2H(p,n pi+)2H. Both the peak energy and the magnitude of the coherent pion production cross section depend very sensitively on the strength of the Delta-N potential. The coherent pions have a peak energy of 300 MeV and a strongly forward peaked angular distribution., RevTeX, 23 pages, 15 figures, uses epsfig macro

The damping mechanisms of the Delta(1232) resonance in nuclei are studied by analyzing the quasi-free decay reactions 12C(pi+,pi+ p)11B and 12C(3He,t pi+ p)11B and the 2p emission reactions 12C(pi+,pp)10B and 12C(3He,t pp)10B. The coincidence cross sections are calculated within the framework of the isobar-hole model. It is found that the 2p emission process induced by the decay of the Delta resonance in the nucleus can be consistently described by a pi+rho+g' model for the Delta+N -> N+N decay interaction., 9 pages, 5 Postscript figures, uses RevTex, psfig.sty. Accepted by Physical Review C