Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 13: Poster Session: Theory
HK 13.10: Poster
Dienstag, 9. März 2004, 13:30–15:30, Foyer
Threshold neutral pion electroproduction off the deuteron — •Hermann Krebs1, Véronique Bernard2, and Ulf-G. Meißner1,3 — 1HISKP (Th), Universität Bonn, Bonn, Germany — 2Physique Théorique, ULP, Strasbourg, France — 3IKP (Th), FZ Jülich, Jülich, Germany
We analyze neutral pion electroproduction off deuterium in chiral perturbation theory. This allows to extract and test the single pion-neutron electroproduction amplitude. The interaction kernel and the deuteron wave functions are calculated consistently with each other in a novel formalism based on the Q-box approach of Kuo and collaborators. The interaction kernel decomposes into single nucleon (impulse approximation) and three-body (meson exchange) pieces. Calculating the latter to third order in the chiral expansion leads to a satisfactory description of the data at photon virtuality Q2 = 0.1 GeV2 from MAMI-B [1]. Here, we report upon improved results based on a complete fourth order calculation of the three–body contribution, with all new parameters fixed from the earlier studies of π N and NN phase shifts [2]. This work is supported in part by the DFG.
[1] H. Krebs, V. Bernard, U.-G. Meißner, Nucl. Phys. A 713 (2003) 405.
[2] H. Krebs, V. Bernard and U.-G. Meißner, in preparation