General properties of the pion production reaction in nuclear matter

The pion production reaction π+ → π+π± on 45Sc was studied at incident pion energies of Tπ+ = 240, 260, 280, 300 and 320 MeV. The experiment was performed using the M11 pion-channel at TRIUMF, and multiparticle events, (π+, π+π±) and (π+, π+π±p), were detected with the CHAOS spectrometer. Results are reported in the form of both differential and total cross sections, and are compared to theoretical predictions and the reaction phase space. The present investigation of the T-dependence of the π+ A → π+π±A' reaction complements earlier examinations of the A-dependence of the reaction, which was measured using 2H, 4He, 12C, 16O, 40Ca and 208Pb targets at ∼280 MeV. Some general properties of the pion-induced pion production reaction in nuclear matter will be presented, based on the combined results of the two studies. (author)