NEUTRAL PION-PHOTOPRODUCTION ON DEUTERIUM IN BARYON CHIRAL PERTURBATION-THEORY TO ORDER Q(4)

Threshold neutral pion photoproduction on the deuteron is studied in t he framework of baryon chiral perturbation theory beyond next-to-leadi ng order in the chiral expansion. To fourth order in small momenta, th e amplitude is finite and a sum of two- and three-body interactions wi th no undetermined parameters. With accurate theoretical and experimen tal input from the single nucleon sector for the proton amplitude, we investigate the sensitivity of the threshold cross section to the elem entary gamma n --> pi(0)n amplitude. A precise measurement of the thre shold cross section for gamma d --> pi(0)d is called for. (C) 1997 Els evier Science B.V.