Coherent and incoherent ${\pi^0}$ photoproduction from the deuteron

U. Siodlaczek; P. Achenbach; J. Ahrens; J.R.M. Annand; H.-J. Arends; R. Beck; R. Bilger; H. Clement; V. Hejny; M. Kotulla; B. Krusche; V. Kuhr; R. Leukel; J.C. McGeorge; V. Metag; R. Novotny; V. Olmos de León; F. Rambo; M. Schepkin; A. Schmidt; I. Seluzhenkov; H. Ströher; G.J. Wagner; Th. Walcher; J. Weiß; F. Wissmann; M. Wolf

doi:doi:10.1007/s100500170120

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2019 Impact factor 2.176

Hadrons and Nuclei

Eur. Phys. J. A 10, 365-371

Coherent and incoherent ${\pi^0}$ photoproduction from the deuteron

U. Siodlaczek¹, P. Achenbach², J. Ahrens³, J.R.M. Annand⁴, H.-J. Arends³, R. Beck³, R. Bilger¹, H. Clement¹, V. Hejny⁵, M. Kotulla², B. Krusche⁶, V. Kuhr⁷, R. Leukel³, J.C. McGeorge⁴, V. Metag², R. Novotny², V. Olmos de León³, F. Rambo⁷, M. Schepkin⁸, A. Schmidt³, I. Seluzhenkov^{8, 9}, H. Ströher⁵, G.J. Wagner¹, Th. Walcher³, J. Weiß², F. Wissmann⁷ and M. Wolf²

¹ Physikalisches Institut, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
² II. Physikalisches Institut, Universität Gieß en, D-35392 Gießen, Germany
³ Institut für Kernphysik, Universität Mainz, D-55099 Mainz, Germany
⁴ Department of Physics and Astronomy, University of Glasgow, Glasgow G128 QQ, UK
⁵ Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich, Germany
⁶ Institut für Physik und Astronomie, Universität Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland
⁷ II. Physikalisches Institut, Universität Göttingen, D-37073 Göttingen, Germany
⁸ Institute for Theoretical and Experimental Physics, Moscow 117218, Russia
⁹ Moscow State Engineering Physics Institute, Moscow 115409, Russia

(Received: 13 February 2001 / Revised version: 11 April 2001 Communicated by M. Garçon)

Abstract
Differential cross-sections for the reactions $d(\gamma,\pi^0)d$ and $d(\gamma,\pi^0)pn$ have been measured at MAMI with the TAPS detector setup in the energy range 140 MeV $< E_\gamma < 306$ MeV. By use of the Glasgow tagging spectrometer an 0.8 MeV energy resolution for photons incident on the target was achieved. The ${\pi^0}$ missing energy resolution was sufficient for a reliable separation of coherent and incoherent channels. The data for the break-up channel exhibit very strong final state interaction effects, whereas the observed angular dependence of the inclusive process $d(\gamma,\pi^0)X$ is in quantitative agreement with predictions for a quasi-free process. The observed absolute $d(\gamma,\pi^0)X$ cross-sections, on the other hand, are significantly smaller than predicted by the quasi-free process for $E_\gamma \gtrsim 250$ MeV. Associating this failure with the ${\pi^0}$ photoproduction on the neutron would suggest that its cross-section is up to 25% below the presently believed value.