Charge Symmetry Breaking in dd → 4He π0 with WASA-at-COSY

Abstract

Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent description of CSB within the framework of chiral perturbation theory. In order to provide still missing data the physics program of WASA-at-COSY comprises two reaction channels. An exclusive measurement of the dd → 3Hen π0 reaction was carried out to obtain precise data on the total cross section as well as on the differential distributions. In addition, the studies on the reaction dd → 4He π0 have been extended towards higher excess energies in order to provide information on the contribution of higher partial waves in the final state.