Influence of the re-scattering process on polarization observables in reaction gamma + d --> p + p + pi- in Delta - resonance region

TL;DR

This paper investigates how pion-nucleon and nucleon-nucleon re-scattering affect polarization observables in the gamma + d -> p + p + pi- reaction within the Delta resonance region, using a diagrammatic and relativistic approach.

Contribution

It introduces a diagrammatic, relativistic-invariant method with K-matrix unitarization to analyze re-scattering effects on polarization observables in this reaction.

Findings

Re-scattering significantly influences polarization observables.

The effects are more pronounced at large proton momenta.

The approach provides a detailed understanding of the reaction dynamics.

Abstract

Influence of the effects of the pion-nucleon and nucleon-nucleon re-scattering on the polarization observables of the reaction gamma + d = p + p + pi- in Delta - isobar region is investigated. Pion-nucleon and nucleon-nucleon re-scattering are studied in the diagrammatic approach. Relativistic-invariant forms of the pion photoproduction and pion-nucleon scattering operators are used. The unitarization procedure in K-matrix approach is applied for the resonance partial amplitudes. It is shown a considerable influence of the re-scattering effects on the polarization observables of this reaction in the Delta - resonance region for the large momenta of the final protons.