Pion-Pion P-Wave Dominance In The Pd -> He-3 Pi(+)Pi(-) Reaction Near Threshold

The cross section for the pd-->He-3 pi(+)pi(-) reaction has been measured in a kinematically complete experiment at a c.m. excess energy of Q = 70 MeV. The striking energy and angular distributions are reproduced in a simple model calculation when it is assumed 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 beam energies which show a strong s-wave ABC enhancement at low pi pi masses. [S0556-2813(99)51111-4].