Lippmann-Schwinger equations using these chiral potentials involves a regulator function of the form $\exp[-(p'^4+p^4)/\lambda^4]$ depending on the momenta, $p$ and $p'$, of the in- and outgoing baryons. The cutoff $\lambda$ is chosen in a reasonable range 500 ... 650 MeV.

A characteristic feature of the resulting $\Lambda N$ S-wave phase shifts that distingushes the chiral EFT-based potential from all earlier phenomenological interactions, such as Jülich’04 [@HM2005] and Nijmegen NSC97f [@Rijken1999], is the following. As there is no (leading-order) one-pion exchange $\Lambda N$ interaction term, the driving intermediate range attraction in this channel comes from the iterative process $\Lambda N \rightarrow \Sigma N \rightarrow \Lambda N$, involving the exchange of two pions. The $\Lambda\Sigma\pi$ coupling as given by SU(3) symmetry implies strong attraction through this second-order process that is partly balanced by the strong short-distance repulsion. The net attraction is seen in the low-energy $^3S_1$ $\Lambda N$ phase shift. The $^1S_0$ phase shift also shows this attractive behavior at low energies but changes sign around a lab momentum of 600 MeV and becomes repulsive. This momentum-dependent repulsion is generated by the short-distance terms at NLO, as can be clearly seen by selectively turning off the $\Lambda\Sigma\pi$ coupling [@Haidenbauer2017]. The repulsive effects 