The two preeminent features of the nucleon-nucleon (NN) interaction are its short-range repulsion and intermediate- to long-range tensor character. These induce strong spatial-spin-isospin NN correlations, which leave their imprint on the structure of ground- and excited-state wave functions. In the present talk I will review how these features influence a variety of nuclear properties---from energy spectra of low-lying states to two-nucleon density distributions to nuclear response functions---as well as the experimental evidence in support of their presence. In particular, I will show [R. Schiavilla, R.B. Wiringa, S.C. Pieper, and J.Carlson, Phys. Rev. Lett. 98, 132501 (2007)] how tensor correlations impact the momentum distribution of np pairs in the ground state of nuclei and make it orders of magnitude larger than that of pp pairs for values of the relative momentum in the range (300--600) MeV/c and vanishing total momentum. This order-of-magnitude difference is seen in all nuclei considered, and has a universal character originating from the tensor components present in any realistic NN interaction. It should be easily observable in two-nucleon knock-out processes. Indeed, a preliminary analysis of (e,e^'np) and (e,e^'pp) reactions in ^12C finds [R. Subedi et al., in preparation] that the pp cross section is suppressed relative to the np by a factor ∼10 in kinematics close to back-to-back emission of the two nucleons.
APS Division of Nuclear Physics Meeting Abstracts
- Pub Date:
- October 2007