| Irfu-08-22
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| Observation of backward peak in the gamma d -> pi0 d cross section near the eta threshold. |
| Y. Ilieva et al (R. de Masi, M. Garçon, F.X. Girod, S. Morrow, F. Sabatié) |
| High-quality cross sections for the reaction gamma+d->pi^0+d have been measured using the CLAS at Jefferson Lab over a wide energy range near and above the eta-meson photoproduction threshold. At backward c.m. angles for the outgoing pions, we observe a resonance-like structure near E_gamma=700 MeV. Our model analysis shows that it can be explained by eta excitation in the intermediate state. The effect is the result of the contribution of the N(1535)S_11 resonance to the amplitudes of the subprocesses occurring between the two nucleons and of a two-step process in which the excitation of an intermediate eta meson dominates. |
