Search

Quasielastic deuteron and triton knockout from 12C and 16O nuclei has been studied infull kinematics using a 0.72-GeV/ c pion beam. The momentum distributions of the intranuclear quasideuteron motion, excitation-energy spectra of the residual nuclei, and the effective numbers N of quasideuterons are determined. The parameters of the quasideuteron intranuclear motion are in reasonable agreement with the results obtained in other beams. The N in the nuclei from 6Li to 16O measured in full kinematics are virtually independent of the atomic number in contrast to the analogous values in the inclusive deuteron-knockout reaction induced by protons. The phenomenon of triton knockout from these nuclei is observed, which makes possible estimation of the cross section of backward pion-triton elastic scattering in yet unexplored regions of energy and momentum transfer. [ABSTRACT FROM AUTHOR]

Rescattering corrections to the impulse approximation for the processes γd → π0d and π-d → π-d are discussed. It is shown that the rescattering effects give a nonnegligible contribution to the real part of these amplitudes. At the same time, the contributions from the imaginary parts of impulse and rescattering corrections drastically cancel each other. This cancellation means that the processes π-d → π0nn and γd → π+nn/π-pp, when the nucleon pair is in the spin triplet state, are strongly suppressed near threshold as required by the Pauli principle. [ABSTRACT FROM AUTHOR]

The reactions pp → dπ[sup +]η and pn → dπ[sup 0]η are of special interest for investigating the a[sub 0](980)(J[sup P] = 0[sup +]) resonance in the process NN → da[sub 0] → dπη. We study some aspects of those reactions within a general formalism and also in a concrete phenomenological model. In particular, it is shown that the presence of nonresonant (i.e., without excitation of the a[sub 0] resonance) contributions to these reactions yields nonvanishing values for specific polarization observables, i.e., to effects like those generated by a[sub 0][sup 0]–f[sub 0] mixing. An experimental determination of these observables for the reaction pvector p → dπ[sup +]η would provide concrete information on the magnitude of those nonresonant contributions to πη production. We also discuss the possibility of extracting information about a[sub 0][sup 0]–f[sub 0] mixing from the reaction pvector n → dπ[sup 0]η with a polarized proton beam.© 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]