New experimental data on the pd → 3
He π+π− reaction obtained with the COSY-MOMO detector below
the three-pion threshold are presented. The reaction was also studied in inverse kinematics with a deuteron beam
and the higher counting rates achieved were especially important at low excess energies. The comparison of
these data with inclusive pd → 3
He X0 rates allowed estimates also to be made of π0π0 production. The results
confirm our earlier findings that, close to threshold, there is no enhancement at low excitation energies in the
π+π− system, where the data seem largely suppressed compared with phase space. Possible explanations for
this behavior, such as strong p waves in the π+π− system or the influence of two-step processes, are explored
