Is there np pairing in N=Z nuclei? art. no. 041303

The binding energies of even-even and odd-odd N = Z nuclei are compared. Af ter correcting for the symmetry energy we find that the lowest T = 1 state in odd-odd N = Z nuclei is as bound as the ground state in the neighboring even-even nucleus, thus providing evidence for isovector np pairing. Howeve r, T = 0 states in add-odd N = Z nuclei are several MeV less bound than the even-even ground states. We associate this difference with the T = 1 pair gap and conclude from the analysis of binding energy differences and blocki ng arguments that there is no evidence for an isoscalar (deuteronlike) pair condensate in N = Z nuclei.