Enhancement of deltaful two-pion exchange nuclear forces

The role of the delta isobar degrees of freedom in nucleon–nucleon scattering is revisited.We attempt to understand why the dimensionally regularized two-pion exchanges with the explicit delta isobar is much stronger than the ones with spectral function regularization.When the cutoff value of spectral function regularization is varied,the isoscalar central component exhibits a rather large cut-off variation.This reveals a surprisingly large numerical factor of the deltaful two-pion exchange potentials.The power counting is adjusted accordingly and we discuss the results and how to improve upon this finding.