Coherent and incoherent pi(0) photoproduction from the deuteron

Siodlaczek, U Achenbach, P Ahrens, J Annand, JRM Arends, HJ Beck, R Bilger, R Clement, H Hejny, V Kotulla, M Krusche, B Kuhr, V Leukel, R McGeorge, JC Metag, V Novotny, R de Leon, VO Rambo, F Schepkin, M Schmidt, A Seluzhenkov, I Stroher, H Wagner, GJ Walcher, T Weiss, J Wissmann, F Wolf, M

U. Siodlaczek et al., Coherent and incoherent pi(0) photoproduction from the deuteron, EUR PHY J A, 10(3), 2001, pp. 365-371

20

INGLESE

Article

Physics

EUROPEAN PHYSICAL JOURNAL A

1434-6001 → ACNP

10

3

2001

365 - 371

ISI

1434-6001(200103)10:3<365:CAIPPF>2.0.ZU;2-Q

Differential cross-sections for the reactions d(gamma,pi (o))d and d(gamma, pi (o))pn have been measured at MAMI with the TAPS detector setup in the en ergy range 140 MeV < E-<gamma> < 306 MeV. By use of the Glasgow tagging spe ctrometer an 0.8 MeV energy resolution for photons incident on the target w as achieved. The <pi>(o) missing energy resolution was sufficient for a rel iable separation of coherent and incoherent channels. The data for the brea k-up channel exhibit very strong final state interaction effects, whereas t he observed angular dependence of the inclusive process d(gamma, pi (o))X i s in quantitative agreement with predictions for a quasi-free process. The observed absolute d(gamma, pi (o))X cross-sections, on, the other hand, are significantly smaller than predicted by the quasi-free process for E-gamma greater than or similar to 250 MeV. Associating this failure with the pi ( o) photoproduction on the neutron would suggest that its cross-section is u p to 25% below the presently believed value.