Determination of the Isotensor Electromagnetic Current from Pion Photoproduction

Abstract

Some consequences of an isotensor component of the electromagnetic current are examined in simple pion photoproduction. An experiment to detect the isotensor contribution in pion photoproduction from deuterium (already suggested by several authors) is reformulated to improve the sensitivity of the test. To estimate how accurately the experiment should be performed, upper bounds on the strength of the isotensor contribution are obtained from our experimental and theoretical knowledge of pion photoproduction from the nucleon. This limit turns out to be much smaller than previously stated in the literature.