Peripheral nucleonnucleon phase shifts and chiral symmetry
Abstract
Within the oneloop approximation of baryon chiral perturbation theory we calculate all onepion and twopion exchange contributions to the nucleonnucleon interaction. In fact we construct the elastic NNscattering amplitude up to and including third order in small momenta. The phase shifts with orbital angular momentum L ≥2 and the mixing angles with J ≥ 2 are given parameter free and thus allow for a detailed test of chiral symmetry in the twonucleon system. We find that for the Dwaves the 2πexchange corrections are too large as compared with empirical phase shifts, signaling the increasing importance of shorter range effects in lower partial waves. For higher partial waves, especially for Gwaves, the modelindependent 2πexchange corrections bring the chiral prediction close to empirical NN phase shifts. We propose to use the chiral NN phase shifts with L ≥ 3 as input in a future phaseshift analysis. Furthermore, we compute the irreducible twopion exchange NN potentials in coordinate space. They turn out to be of van der Waals type, with exponential screening of twopion mass range.
 Publication:

Nuclear Physics A
 Pub Date:
 February 1997
 DOI:
 10.1016/S03759474(97)005861
 arXiv:
 arXiv:nuclth/9706045
 Bibcode:
 1997NuPhA.625..758K
 Keywords:

 Nuclear Theory;
 High Energy Physics  Phenomenology
 EPrint:
 30 pages, TeX,12 figures in ps , submitted to Nucl. Phys. A