Measurement of the Tensor Analyzing Power T20 in the Fragmentation of 9 GeV Tensor Polarized Deuterons into Cumulative Pions

Tensor analyzing power T 20 of the reaction d ↑ A → π–(0°)X was measured in the fragmentation of 9 GeV deuterons into pions with momenta from 3.5 to 5.3 GeV/c on hydrogen, beryllium and carbon targets. This momentum range corresponds to the region of cumulative production with the cumulative variable x c from 1.08 to 1.76. The values of T 20 were found to be small and consistent with positive values in contradiction with the predictions based on a direct mechanism assuming N N collision between a high momentum nucleon in the deuteron and a target nucleon (N N → N N π).