Speaker
Prof.
Stefan Frauendorf
(University Notre Dame)
Description
The short-range proton-neutron interaction favors the formation of p-n pairs with parallel or antiparallel spin. They may appear as three species: T=1,J=0 (“isovector pairing”), T=0,J=1 (“isoscalar pairing”), and T=0, J=2j (“spin-aligned”). In N≈Z nuclei, so far accessible, there is clear evidence for strong isovector pair correlations. Evidence for isoscalar pair correlations is elusive. The reason seems suppression by spin-orbit splitting. Weakening of spin-orbit splitting is predicted for the region N≈Z>50, which may lead to a rise of isoscalar pair correlations. Based on Shell Model calculations, the formation of a “condensate” of spin-aligned pairs was suggested. The nature of such spin-aligned coupling scheme, its coexistence with isovector pairing, and the limits of pair classification due to the finite nucleon number will be discussed.
Author
Prof.
Stefan Frauendorf
(University Notre Dame)
