Tübingen 2003 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 13: Poster-Sitzung: Theorie
HK 13.10: Poster
Dienstag, 18. März 2003, 13:30–15:30, Foyer
Chiral dynamics of deeply bound pionic atoms — •Norbert Kaiser1, Evgeni Kolomeitsev2 und Wolfram Weise1,2 — 1Physik Department T39, Technische Universität München, D-85747 Garching — 2ECT*, Villa Tambosi, I-Villazzano (Trento)
We present and discuss a systematic calculation, based on two-loop in-medium chiral perturbation theory, of the pion-nuclear s-wave optical potential. A proper treatment of the explicit energy dependence of the off-shell pion self-energy together with electromagnetic gauge invariance of the Klein-Gordon equation turns out to be crucial. Accurate date for the binding energies and widths of the 1s and 2p levels of pionic 205Pb and 205Pb are well reproduced, and the notorious missing repulsion" in the pion-nuclear s-wave optical potential can be accounted for. Similarly good results are obtained for the deeply bound pionic atom states in Sn-isotopes. The connection with the in-medium change of the pion decay constant is clarified. To leading order, the energy dependence effects can be interpreted this way in an equivalent energy independent optical potential.
[1] preprint: nucl-th/0207090 Work supported in part by BMBF, DFG and GSI.