Three-pion exchange nucleon-nucleon potentials with virtual $\Delta$-isobar excitation

TL;DR

This paper derives analytical expressions for three-pion exchange nucleon-nucleon potentials involving $elta$-isobar excitation, revealing a primarily repulsive isoscalar central potential from these mechanisms.

Contribution

It provides new analytical formulas for three-pion exchange NN-potentials with $elta$-isobar excitation, enhancing understanding of intermediate-range nuclear forces.

Findings

Main effect is a repulsive isoscalar central NN-potential.

Derived spectral-functions in momentum-space.

Coordinate-space potentials show significant repulsion.

Abstract

The nucleon-nucleon interaction arising from the exchange of three pions and the excitation of $\Delta(1232)$-isobars in intermediate states is studied. Approximating the $\Delta$-propagator by the inverse $\Delta$N mass-splitting, analytical expressions are derived for the spectral-functions of the isoscalar and isovector central, spin-spin and tensor NN-potentials in momentum-space. A trans- lation of the spectral-functions into coordinate-space potentials reveals that the main effect of these specific exchange and excitation mechanisms is a repulsive isoscalar central NN-potential.