P-wave dominance in the pd -> 3He pi+ pi- reaction near threshold   measured with the MOMO experiment at COSY
  The cross section of the pd -> 3He pi+ pi - reaction has been measured at the MOMO facility in a kinematically complete experiment at a c. m. excess energy of Q = 70 MeV. The energy and angular distributions show that the reaction is dominated by p-wave pi+ pi- pairs. This is in complete contrast to the results of inclusive measurements at somewhat higher energies which show a strong s-wave ABC enhancement at low pi pi masses. There are however indications of p-wave pion pairs from other experiments at low Q. 
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C.   Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczy...