DIFFERENTIAL CROSS-SECTIONS FOR RADIATIVE-CAPTURE OF PIONS ON HYDROGEN IN THE DELTA(1232) REGION - TEST OF THE ISOSPIN STRUCTURE AND TERT-SYMMETRY OF HADRONIC ELECTROMAGNETIC-INTERACTIONS

Radiation capture of π- on hydrogen has been measured in the momentum range from pπ- = 210 MeV/c to pπ- = 385 MeV/c and for c.m. angles between 30° and 120°, covering the Δ (1232) resonance. The unambiguous separation of the events from the charge exchange background is based on precise neutron time-of-flight measurements. Detector efficiencies were carefully determined in separate experiments. The experimental results are in good agreement with those of the inverse reaction and with most recent multipole analyses. An upper limit of ±2% can be set on the contribution of the isotensor term to the transition amplitude. A time reversal violating phase, when added to the resonant M1+ 3 amplitude in the Donnachie-Shaw model, is found to be consistent with zero. © 1979.