Charge symmetry breaking in $dd\rightarrow ^{4}He\pi ^{0}$ with WASA-at-COSY

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 this work the experimental studies on the reaction dd\rightarrow $^{4}He\pi ^{0}$ have been extended towards higher excess energies in order to provide information on the contribution of p-waves in the final state. For this, an exclusive measurement has been carried out at a beam momentum of $p_{d}=1.2$ GeV/c using the WASA-at-COSY facility. The total cross section amounts to $\sigma _{tot} = (118 \pm 18_{stat} \pm 13_{sys} \pm 8_{ext}) pb$ and first data on the differential cross section are consistent with s-wave pion production.