The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.

Final report for a research program in theoretical nuclear physics to develop methods and computer programs to perform ab initio calculations for light nuclei ranging from Helium to Oxygen. The method employed is based effective interaction theory within the framework of the shell model. The principal accomplishments were: (1) participation in the validation of ab initio for {sup 4}He; the first study of A = 6 nuclei with the realistic, non-local CD-Bonn potential; (2) a study of ''intruder'' states in {sup 8}Be, (3) the first shell-model calculations implementing three-body clusters in the effective interaction for nuclei with A> 4; (4) the discovery that two-nucleon interactions by themselves are inadequate to describe the structure of the nucleus {sup 10}B, which provides proof that three-nucleon forces affect nuclear structure; (5) first calculations including the Tucson-Melbourne three-nucleon force, which gives better agreement with the experimental spectrum for {sup 10}B and (6) the development of a new shell-model code designed for public release.

There has been significant progress in the ab initio approaches to the structure of light nuclei. One such method is the ab initio no-core shell model (NCSM). Starting from realistic two- and three-nucleon interactions this method can predict low-lying levels in p-shell nuclei. In this contribution, we present a brief overview of the NCSM with examples of recent applications. We highlight our study of the parity inversion in {sup 11}Be, for which calculations were performed in basis spaces up to 9{Dirac_h}{Omega} (dimensions reaching 7 x 10{sup 8}). We also present our latest results for the p-shell nuclei using the Tucson-Melbourne TM three-nucleon interaction with several proposed parameter sets.

In the present edition, a number of new features have been added. First of all, a number of typographical errors that had crept into the text have been corrected. More importantly, a number of new examples, figures and smaller sections have been added. In evaluating the two-body matrix elements which characterize the residual interaction, attention has been paid to the multipole expansion and insight into the importance of various multipoles is presented. The 18 example of 0 is now worked out for all the different angular momentum states in the section on configuration mixing. Some additional comments on how to determine one- and two-body matrix elements in jn configurations, on isospin and the application of isospin to the study of light odd-odd nuclei are included. In Chap. 3, a small section on the present use of large-scale shell model calculations and a section on experimental tests of how a nucleon actually moves inside the nucleus (using electromagnetic probing of nucleonic motion) has been added. In Chap. 4, some recent applications of the study of quadrupole motion in jn particle systems (with reference to the Po, Rn, Ra nuclei) are presented. In the discussion of magnetic dipole moments, the effects and importance of collective admixtures are pointed out and discussed. In Chap. 5, some small additions relating to the particle-hole conjugation and to the basic Hartree-Fock theory have been made. In Chap.

The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. In addition to the complex nature of nuclear forces, one faces the quantum-mechanical many-nucleon problem governed by an interplay between bound and continuum states. In recent years, significant progress has been made in ab initio nuclear structure and reaction calculations based on input from QCD employing Hamiltonians constructed within chiral effective field theory. In this contribution, we present one of such promising techniques capable of describing simultaneously both bound and scattering states in light nuclei. By combining the resonating-group method (RGM) with the ab initio no-core shell model (NCSM), we complement a microscopic cluster approach with the use of realistic interactions and a microscopic and consistent description of the clusters. We discuss applications to light nuclei scattering, radiative capture and fusion reactions.

There has been a significant progress in ab initio approaches to the structure of light nuclei. Starting from realistic two- and three-nucleon interactions the ab initio no-core shell model (NCSM) can predict low-lying levels in p-shell nuclei. It is a challenging task to extend ab initio methods to describe nuclear reactions. In this contribution, we present a brief overview of the NCSM with examples of recent applications as well as the first steps taken toward nuclear reaction applications. In particular, we discuss cross section calculations of p+[sup 6]Li and [sup 6]He+p scattering as well as a calculation of the astrophysically important [sup 7]Be(p, [gamma])[sup 8]B S-factor.