Neutron-proton pairing in the N=Z radioactive -shell Nuclei Ni and Fe probed by pair transfer
B. Le Crom (Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France)
; M. Assié (Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France)
; Y. Blumenfeld (Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France); J. Guillot (Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France); H. Sagawa (Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, Japan); et al - Show all 52 authors
The isovector and isoscalar components of neutron-proton pairing are investigated in the N=Z unstable nuclei of the fp-shell through the two-nucleon transfer reaction (p,$^{3}$He) in inverse kinematics. The combination of particle and gamma-ray detection with radioactive beams of $^{56}$Ni and $^{52}$Fe, produced by fragmentation at the GANIL/LISE facility, made it possible to carry out this study for the first time in a closed and an open-shell nucleus in the fp-shell. The transfer cross-sections for ground-state to ground-state (J=0$^{+}$, T=1) and to the first (J=1$^{+}$, T=0) state were extracted for both cases together with the transfer cross-section ratios . They are compared with second-order distorted-wave born approximation (DWBA) calculations. The enhancement of the ground-state to ground-state pair transfer cross-section close to mid-shell, in $^{52}$Fe, points towards a superfluid phase in the isovector channel. For the “deuteron-like” transfer, very low cross-sections to the first (J=1$^{+}$, T=0) state were observed both for $^{56}$Ni(p,$^{3}$He) and $^{52}$Fe(p,$^{3}$He) and are related to a strong hindrance of this channel due to spin-orbit effect. No evidence for an isoscalar deuteron-like condensate is observed.