Large-Nc operator analysis of hyperon–nucleon interactions in SU(3) chiral effective field theory.

Abstract We study octet–octet baryon (J P = 1 2 +) contact interactions in SU(3) chiral effective field theory by using large- N c operator analysis. By applying the 1 / N c expansion of the Hartree Hamiltonian, we find 15 operators in the octet–octet baryon potential where 4 operators for the leading order (LO) and 11 for the next-to-next-to-leading order (NNLO). The large- N c operator analysis of octet–octet baryon matrix elements reduces the number of free parameters from 15 to 6 at the LO of the 1 / N c expansion. The application of large- N c sum rules to the Jülich model of hyperon–nucleon (YN) interactions at the LO of the chiral expansion reduces the model parameters to 3 from 5 at the LO of 1 / N c expansion. We find that the values of LECs fitted to YN scattering data in Ref. [21] in the relativistic covariant ChEFT (EG) approach are more consistent with the predictions of the large- N c analysis than in the heavy baryon (HB) formalism approach. [ABSTRACT FROM AUTHOR]