The pd→He3ηπ0 reaction at Tp=1450 MeV

The cross section for the pd→He3ηπ0 reaction has been measured at a beam energy of 1450 MeV using the WASA detector at the CELSIUS storage ring. The 3He was detected in coincidence with four photons from the decays of the two mesons. The data indicate that the production mechanism involves the formation of the Δ(1232) isobar. Although the beam energy does not allow the full peak of this resonance to be seen, the invariant mass distributions of all three pairs of final particles are well reproduced by a phase space Monte Carlo simulation weighted with the p-wave factor of the square of the π0 momentum in the He3π0 system.