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HK: Hadronen und Kerne

HK 40: Electromagnetic Probes VI, NN-Correlations

HK 40.3: Gruppenbericht

Dienstag, 17. März 1998, 18:00–18:30, F

Meson-induced correlations of nucleons in nuclear Compton scattering — •M.-Th. Hütt¹, A.I. Milstein², and M. Schumacher¹ — ¹II. Physikalisches Institut, D-37073 Göttingen, Germany — ²Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia

Within a German-Russian collaboration on theoretical aspects of nuclear Compton scattering we formulated a model-description for parts of the nuclear Compton amplitude. Here we will describe our results for the mesonic part of the amplitude.

The non-resonant (seagull) contribution to the nuclear Compton amplitude at low energies is strongly influenced by nucleon correlations arising from meson exchange. In particular, the appearance of polarizability modifications as a result of photon scattering by correlated nucleons has recently been established [1].

Using the same framework as in [1], a modified Fermi gas model, where nuclear correlation functions are obtained with the help of perturbation theory, we study the problem of exchange form factors. In addition, we discuss the dependence of the mesonic seagull amplitude on the nuclear radius and the influence of a realistic nuclear density on this amplitude.

We found [2] that different form factors appear for the static part (proportional to the enhancement constant κ ) of the mesonic seagull amplitude and for the parts, which contain the contribution from electromagnetic polarizabilities.

[1] M.-Th. Hütt and A.I. Milstein, Nucl. Phys. A609 (1996) 391

[2] M.-Th. Hütt and A.I. Milstein, Phys. Rev. C in press