Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 5: Theory I
HK 5.1: Gruppenbericht
Montag, 8. März 2004, 15:45–16:15, D
Novel approach to nuclear forces from effective field theory — •Ulf-G. Meißner1,2, Evgeny Epelbaum3, and Walter Glöckle4 — 1HISKP (Th), Universität Bonn, Bonn, Germany — 2IKP (Th), FZ Jülich, Jülich, Germany — 3Jefferson Lab, TH Div, Newport News, USA — 4RUB, TP II, Bochum, Germany
We report on a new formulation to calculate the forces between two, three, … nucleon from chiral effective field theory. We have developed a cut-off scheme for pion loop integrals, in particular the two-pion exchange, based on spectral function regularization [1]. This scheme allows for a consistent implementation of the constraints from pion-nucleon scattering. It leads to a much improved description of the partial waves with l ≥ 2 compared to the calculation utilizing dimensional regularization. We have also studied the low partial waves and deuteron properties at next-to-leading order [2] and find an overall good description of the two-nucleon force. We also show that the numerical values of the coupling constants of the four-nucleon contact operators, that are determined from a fit to the low partial waves, can be understood in terms of resonance saturation. This allows for a connection with more conventional boson exchange phenomenology. At this meeting, we present results for the partial waves and deuteron properties obtained at N3LO [3], which are of the same precision as one obtains when employing the so–called high precision potentials.
[1] E. Epelbaum et al., arXiv:nucl-th/0304037, Eur. Phys. J. A, in print
[2] E. Epelbaum et al., arXiv:nucl-th/0308010, Eur. Phys. J. A, in print
[3] E. Epelbaum, W. Glöckle and U.-G. Meißner, in preparation