We investigate the role of the ${\mathrm{\Delta }}^{+}$ mass and the magnetic dipole coupling parameters in the extraction of the ratio of electric quadrupole to magnetic dipole amplitudes (EMR) in the ${\mathrm{\Delta }}^{+}$→rγ transition. We show that existing data on single-pion photoproduction do not allow as wide a range (±5% ) of values for the EMR as concluded in a recent paper by Slaughter and Oneda [Phys. Rev. D 49, 323 (1994)].

• Received 7 October 1994

DOI:https://doi.org/10.1103/PhysRevD.51.3966