Two-pion exchange electromagnetic current in chiral effective ﬁeld theory using the method of unitary transformation
Forschungszentrum Jülich, Institut für Kernphysik (IKP-3) and
Jülich Center for Hadron Physics, D-52425
2 Helmholtz-Institut für Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany
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Using the method of unitary transformation in combination with chiral eﬀective ﬁeld theory we derive the two-pion exchange contributions to the two-nucleon electromagnetic current. A formal deﬁnition of the current operator in this scheme and the power counting is presented. We discuss the implications of additional unitary transformations that have to be present to ensure the renormalizability of the one-pion exchange current. Further, we give explicit and compact results for the current in coordinate-space.
© Owned by the authors, published by EDP Sciences, 2010