Investigation of the dd -> 3He n \pi 0 reaction with the FZ J\"ulich WASA-at-COSY facility

TL;DR

This study provides the first detailed measurements of the dd -> 3He n π0 reaction at 1.2 GeV/c, including total and differential cross sections, using a combined phenomenological model to interpret the data.

Contribution

It presents the first experimental data on this reaction's cross sections and differential distributions, analyzed with a novel combination of quasi-free and partial wave models.

Findings

Total cross section measured as 2.89 μb

Quasi-free processes contribute 38% of the cross section

p-wave contributions are significant in the final state

Abstract

An exclusive measurement of the dd -> 3He n \pi 0 reaction was carried at a beam momentum of p = 1.2 GeV/c using the WASA-at-COSY facility. For the first time data on the total cross section as well as differential distributions were obtained. The data are described with a phenomenological approach based on a combination of a quasi-free model and a partial wave expansion for three-body reaction. The total cross section is found to be \sigma(tot) = (2.89 +- 0.01(stat) +- 0.06(sys) +- 0.29(norm)) \mu b. The contribution of the quasi-free processes (with the neutron being target or beam spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of the phase space. The remaining part of the cross section can be described within a partial wave decomposition indicating the significance of p-wave contributions in the final state.