Threshold $\pi^0$ production from the neutron in d( $\gamma,\pi^0$n)p

D. L. Hornidge

Department of Physics, University of Saskatchewan
and
Institut für Kernphysik, J.J.-Becherweg 45, D-55099 Mainz, Germany

A significant body of experimental results now exists for the proton photo-pion amplitudes near threshold and are in good agreement with ChPT predictions. Due to the experimental intricacies involved, there is a clear lack of data in the threshold region for the neutron. Preliminary attempts to determine the neutron amplitudes using the coherent production from the deuteron were hampered by the difficulties in separating out nuclear effects. For these reasons, a measurement of $\pi^0$ photoproduction in the threshold region from the neutron via the d( $\gamma,\pi^0$n)p reaction channel has been performed using the Mainz Microtron (MAMI). Photons in the energy range $E_{\gamma}=95.7-208.5$ MeV were tagged using the Glasgow tagger, the TAPS spectrometer was employed to detect the neutral-pion decay photons, and a segmented liquid-scintillator detector covering the angular range $\theta_n = 21.5^\circ \pm 8.5^\circ$, $\phi_n = 0.0^\circ \pm 8.5^\circ$ was used to detect recoil neutrons under quasi-free kinematical conditions. Preliminary results will be presented.

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