Density-dependent NN-interaction from subsubleading chiral 3N-force: Intermediate-range contributions

Abstract

From the subsubleading chiral three-nucleon force [intermediate-range contributions, published in Phys. Rev. C\,87, 054007 (2013)] a density-dependent NN-interaction $V_{\text{med}}$ is derived in isospin-symmetric nuclear matter. Following the division of the pertinent 3N-diagrams into two-pion-one-pion exchange topology and ring topology, one evaluates for these all selfclosings and concatenations of nucleon-lines to an in-medium loop. In the case of the $2\pi 1\pi$-exchange topology, the momentum- and $k_f$-dependent potentials associated with the isospin-operators ($1$ and ${\vec{\tau }}_1\cdot {\vec{\tau }}_2$) and five independent spin-structures require at most one numerical integration. For the more challenging (concatenations of the) ring diagrams proportional to $c_{1,2,3,4}$, one ends up with regularized double-integrals ${\int }_0^{\lambda }drr{\int }_0^{\pi /2}d\psi$ from which the ${\lambda }^2$-divergence has been subtracted and the logarithmic piece $\sim \ln (m_{\pi }/\lambda )$ is isolated. The derived semi-analytical results are most helpful to implement the subsubleading chiral 3N-forces into nuclear many-body calculations.

Comments: 17 pages, 1 figure, to be published in Phys. Rev. C