Radiative decay of the Δ resonance: Analyzing powers for π-p→→γn

The polarized target asymmetry AN for π-p→→γn has been measured by coincident detection of the γ and the neutron at several angles across the Δ resonace energy region. A high-resolution NaI γ spectrometer together with good time-of-flight information for the neutron resulted in excellent separation of this radiative capture reaction from the much higher cross-section charge exchange reaction π-p→→π0n. Statistical uncertainties are ΔAN=0.02-0.04, representing a significant improvement over previous results. The new data are discussed in the context of recent theoretical models.