Intermediate resonance excitation in the γp→pπ 0π0 reaction

J. Ahrens, S. Altieri, J. R.M. Annand, G. Anton, H. J. Arends, K. Aulenbacher, R. Beck, C. Bradtke, A. Braghieri, N. Degrande, N. D'Hose, H. Dutz, S. Goertz, P. Grabmayr, K. Hansen, J. Harmsen, D. Von Harrach, S. Hasegawa, T. Hasegawa, E. HeidK. Helbing, H. Holvoet, L. Van Hoorebeke, N. Horikawa, T. Iwata, O. Jahn, P. Jennewein, T. Kageya, B. Kiel, F. Klein, R. Kondratiev, K. Kossert, J. Krimmer, M. Lang, B. Lannoy, R. Leukel, V. Lisin, T. Matsuda, J. C. McGeorge, A. Meier, D. Menze, W. Meyer, T. Michel, J. Naumann, A. Panzeri, P. Pedroni, T. Pinelli, I. Preobrajenski, E. Radtke, E. Reichert, G. Reicherz, Ch Rohlof, G. Rosner, T. Rostomyan, D. Ryckbosch, M. Sauer, B. Schoch, M. Schumacher, B. Seitz, T. Speckner, N. Takabayashi, G. Tamas, A. Thomas, R. Van De Vyver, A. Wakai, W. Weihofen, F. Wissmann, F. Zapadtka, G. Zeitler

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54 Citations (Scopus)


The helicity dependence of the total cross section for the γ→p→→pπ0π0 reaction has been measured for the first time at incident photon energies from 400 to 800 MeV. The measurement, performed at the tagged photon beam facility of the MAMI accelerator in Mainz, used the large acceptance detector DAPHNE and a longitudinally polarized frozen-spin target. This channel is found to be excited predominantly when the photon and proton have a parallel spin orientation, most likely due to the intermediate production of the D13(1520) resonance. However, the contribution of the antiparallel spin configuration, arising from other reaction mechanisms, is also not negligible. This result gives important new information to resolve the existing model discrepancies in the identification of the nucleon resonances contributing to this channel.

Original languageEnglish
Pages (from-to)173-180
Number of pages8
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number3-4
Publication statusPublished - Sept 29 2005
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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