Nucleon and nucleon-pair momentum distributions in A ≤ 12 nuclei

Background: Momentum distributions of individual nucleons and nucleon pairs reflect features of the short-range structure of nuclei and provide useful insights into various reactions on nuclei, such as (e, e'p) and (e, e' pp / pn) electrodisintegration processes or neutrino-nucleus interaction experiments. Purpose: To provide the nuclear physics community with the results (available online) of a systematic study of single-nucleon momentum distributions and nucleon-pair and nucleon-cluster momentum distributions for A <= 12 nuclei. Method: The realistic Argonne nu(18) two-nucleon and Urbana X three-nucleon potentials are used to generate accurate variational Monte Carlo wave functions for the A <= 12 nuclei; quantum Monte Carlo methods are used to calculate the momentum distributions. Results: Single-nucleon distributions are given, broken down into proton and neutron components and spin-up and spin-down components where appropriate. Nucleon-pair momentum distributions are given either in pair spin and isospin ST projection or for pp, pn, and nn pairs. Nucleon-cluster momentum distributions include dp in He-3, tp and dd in He-4, alpha d in Li-6, alpha t in Li-7, and alpha alpha in Be-8. Conclusions: The momentum distributions exhibit common characteristic shapes, with tensor correlations (or lack thereof) playing a dominant role in the 1.5-3 fm(-1) range, while spin-isospin correlations dominate at higher momenta.