The nucleon-nucleon interaction up to sixth order in the chiral expansion

Ruprecht Machleidt, David R. Entem, Norbert Kaiser, Yevgen Nosyk

Research output: Contribution to journalConference articlepeer-review


We calculate the nucleon-nucleon (NN) interaction up to sixth order (N5LO) of chiral perturbation theory. Previous studies extended only up to N3LO (fourth order) and typically showed a surplus of attraction, particularly, when the pN LECs from pN analysis were applied consistently. Furthermore, the contributions at N2LO and N3LO are both fairly sizeable, thus, raising concerns about the convergence of the chiral expansion. We show that the N4LO contribution is repulsive and, essentially, cancels the excessive attraction of N3LO. The N5LO contribution turns out to be considerably smaller than the N4LO one, hence, establishing the desired trend of convergence. The predictions at N5LO are in excellent agreement with the empirical phase shifts of peripheral partial waves.

Original languageEnglish
Article number112
JournalProceedings of Science
StatePublished - 2015
Event8th International Workshop on Chiral Dynamics, CD 2015 - Pisa, Italy
Duration: 29 Jun 20153 Jul 2015


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