Evidence for a spin-aligned neutron–proton paired phase from the level structure of 92 Pd

new spin on neutron–proton pairs In nuclei with equal neutron ( N ) and proton ( Z ) numbers, the observed enhanced neutron–proton correlations are predicted to favour isoscalar neutron–proton pairing, an unusual interaction that is distinct from normal nuclear superfluidity. Now, in a major experiment at the GANIL heavy-ion accelerator in France, observations of excited states of the N = Z = 46 palladium nucleus 92 Pd provide evidence for spin-aligned isoscalar neutron–proton pairing that is rather different to that predicted, and which has not been seen previously in nuclei.