Angular asymmetries in the reactions pp \to dπ^+ηand pn \to dπ^0ηand a_0-f_0 mixing

Abstract

The reactions pp\to dπ^+ηand pn\to dπ^0ηare of special interest for investigating the a_0(980) (J^P=0^+) resonance in the process NN \to da_0 \to 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_0 resonance) contributions to these reactions yields nonvanishing values for specific polarization observables, i.e. to effects like those generated by a_0-f_0 mixing. An experimental determination of these observables for the reaction pp\to dπ^+ηwould provide concrete information on the magnitude of those nonresonant contributions to πηproduction. We discuss also the possibility of extracting information about a_0-f_0 mixing from the reaction pn \to dπ^0ηwith polarized proton beam.

14 pages, 3 figures