The nuclear force embodies various facets of the nucleon-nucleon interaction which are responsible of changes in nuclear structure, like magic numbers, from the stability to the drip lines. Characterizing this nucleon-nucleon interaction remains one fundamental question in nuclear physics. Thanks to the radioactive beams and detection setups which are now available, new constraints can be given for nuclei in extreme conditions, like close to the driplines for example.
The 26F, which can be viewed as a closed 24O core plus one deeply bound proton and one weakly bound neutron, offers the opportunity to study the effect of the continuum on the proton-neutron interaction. Several techniques, like in-beam  and delayed  g-ray spectroscopies, time-of-flight technique  or exclusive one-proton knockout measurement , at different facilities like GANIL and GSI, have been used to probe this interaction in 26F. Results of these experiments will be presented and discussed in the context of comparison to calculations using the independent-particle shell model and the ab initio valence-space in-medium similarity renormalization group method.
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