The contents of this review reflect some of the shifts of emphasis that are occurring among the fields of astrophysics, nuclear physics, and elementary particle physics. Particle physics has made great advances in the unification of the fundamental forces of nature. Discussions and planning for a next big step in accelerator-colliders are presented. The technology of superconducting magnet systems as well as the fundamental physical principles of particle accelerators are discussed. Also presented are: high-resolution electronic particle detectors; nuclear physics changes such as pion interactions within nuclei; discussion of future relativistic heavy-ion colliders; the role of rotational degrees of freedom in heavy-ion collisions at low and moderate energies; hyperon beta decays; and the analysis of materials via nuclear reaction techniques. Neutrinos, their interactions and possible masses, have an important bearing on cosmology and the matter density of the universe in addition to their inherent interest in the microscopic world and this is also examined.

Annual Review of Nuclear and Particle Science

This article provides an overview of the basic principles of the physics of quantum halo systems, defined as bound states of clusters of particles with a radius extending well into classically forbidden regions. Exploiting the consequences of this definition, the authors derive the conditions for occurrence in terms of the number of clusters, binding energy, angular momentum, cluster charges, and excitation energy. All these quantities must be small. The article discusses the transitions between different cluster divisions and the importance of thresholds for cluster or particle decay, with particular attention to the Efimov effect and the related exotic states. The pertinent properties can be described by the use of dimensionless variables. Then universal and specific properties can be distinguished, as shown in a series of examples selected from nuclear, atomic, and molecular systems. The neutron dripline is especially interesting for nuclei and negative ions for atoms. For molecules, in which the cluster division comes naturally, a wider range of possibilities exists. Halos in two dimensions have very different properties, and their states are easily spatially extended, whereas Borromean systems are unlikely and spatially confined. The Efimov effect and the Thomas collapse occur only for dimensions between 2.3 and 3.8 and thus not for 2. High-energy reactions directly probe the halo structure. The authors discuss the reaction mechanisms for high-energy nuclear few-body halo breakup on light, intermediate, and heavy nuclear targets. For light targets, the strong interaction dominates, while for heavy targets, the Coulomb interaction dominates. For intermediate targets these processes are of comparable magnitude. As in atomic and molecular physics, a geometric impact-parameter picture is very appropriate. Finally, the authors briefly consider the complementary processes involving electroweak probes available through beta decay, electromagnetic transitions, and capture reactions.

Structure and reactions of quantum halos

Nuclear magic numbers: New features far from stability

Large deformation of the very neutron-rich nucleus 32Mg from intermediate-energy Coulomb excitation

The nuclear shell model towards the drip lines

2H(18F,pα)15Nreaction applied to nova γ-ray emission

The observed primordial ${}^{7}$Li abundance in metal-poor halo stars is found to be lower than its Big-Bang nucleosynthesis (BBN) calculated value by a factor of approximately three. Some recent works suggested the possibility that this discrepancy originates from missing resonant reactions which would destroy ${}^{7}$Be, parent of ${}^{7}$Li. The most promising candidate resonances which were found include a possibly missed 1${}^{\ensuremath{-}}$ or 2${}^{\ensuremath{-}}$ narrow state around 15 MeV in the compound nucleus ${}^{10}$C formed by ${}^{7}$Be+${}^{3}$He and a state close to 7.8 MeV in the compound nucleus ${}^{11}$C formed by ${}^{7}$Be+${}^{4}$He. In this work, we studied the high excitation energy region of ${}^{10}$C and the low excitation energy region in ${}^{11}$C via the reactions ${}^{10}$B(${}^{3}$He,$t$)${}^{10}$C and ${}^{11}$B(${}^{3}$He,$t$)${}^{11}$C, respectively, at the incident energy of 35 MeV. Our results for ${}^{10}$C do not support ${}^{7}$Be+${}^{3}$He as a possible solution for the ${}^{7}$Li problem. Concerning ${}^{11}$C results, the data show no new resonances in the excitation energy region of interest and this excludes the ${}^{7}$Be+${}^{4}$He reaction channel as an explanation for the ${}^{7}$Li deficit.

Didier Beaumel

Papers

2H(18F,pα)15Nreaction applied to nova γ-ray emission

Search for new resonant states in C-10 and C-11 and their impact on the cosmological lithium problem

Search for new neutron-rich nuclei with a 70A MeV 48Ca beam

Anharmonicity in extended RPA

Excitation of giant resonances in heavy-ion reactions at intermediate energies: Results from the 40Ar + 90Zr and 208Pb experiments at 41 MeVu