π0-η meson mixing in pd3Hπ+/3Heπ0 reactions

Beam momentum dependence of the experimental cross sections for pd-->(3)Hpi(+)/(3)Hepi(0) reactions have been studied at large proton-pion relative angle. The measurements were performed for five beam momenta in the region of the eta meson production threshold. Observed behavior of the measured cross sections ratio reveals manifestations of the isospin symmetry breaking effects. A simple model allows one to interpret the isospin symmetry breaking in terms of pi(0)-eta meson mixing. Based on that model analysis of the experimental results leads to the mixing angle value of 0.006+/-0.005 rad.