UNIVERSALITY OF NUCLEON-NUCLEON SHORT-RANGE CORRELATIONS AND NUCLEON MOMENTUM DISTRIBUTIONS

By analyzing recent microscopic many-body calculations of few-nucleon systems and complex nuclei performed by different groups in terms of realistic nucleon-nucleon (NN) interactions, it is shown that NN short-range correlations (SRCs) have a universal character, in that the correlation hole that they produce in nuclei appears to be almost A-independent and similar to the correlation hole in the deuteron. The correlation hole creates high-momentum components, missing in a mean-field (MF) description and exhibiting several scaling properties and a peculiar spin-isospin structure. In particular, the momentum distribution of a pair of nucleons in spin-isospin state (ST) = (10), depending upon the pair relative (k(rel)) and center-of-mass (c.m.) (K-c.m.) momenta, as well as upon the angle Theta between them, exhibits a remarkable property: in the region k(rel) greater than or similar to 2 fm(-1) and K-c.m. less than or similar to 1 fm(-1), the relative and c.m. motions are decoupled and the two-nucleon momentum distribution factorizes into the deuteron momentum distribution and an A-dependent momentum distribution describing the c.m. motion of the pair in the medium. The impact of these and other properties of one- and two-nucleon momentum distributions on various nuclear phenomena, on ab initio calculations in terms of low-momentum interactions, as well as on ongoing experimental investigations of SRCs, are briefly commented.