Clusters and halos in light nuclei

Abstract

The fermionic molecular dynamics approach uses Gaussian wave packets as single-particle basis states. Many-body basis states are Slater determinants projected on parity, angular momentum and total linear momentum. The wave-packet basis is very flexible - FMD contains harmonic oscillator shell model and Brink-type cluster states as special cases. The parameters of the wave packets are obtained by variation. A realistic effective interaction derived from the Argonne V18 interaction by means of the unitary correlation operator method is employed. We discuss the fully microscopic calculation of the 3He(alpha,gamma)7Be capture reaction within the FMD approach. The model space contains frozen cluster configurations at large distances and polarized configurations in the interaction region. The polarized configurations are essential for a successful description of the 7Be bound state properties and for the S- and D-wave scattering states. The calculated cross section agrees well with recent measurements regarding both the absolute normalization and the energy dependence. We also discuss the structure of the cluster states, including the famous Hoyle state, in 12C. From the two-body densities we conclude that the Hoyle state has a spatially extended triangular alpha-cluster structure, whereas the third 0+ state features a chain-like obtuse triangle structure. We also calculate the N hbar Omega decomposition of our wave functions to illuminate the challenges of no-core shell model calculations for these cluster states.

7 pages, Proceedings of Horizons of Innovative Theories, Experiments, and Supercomputing in Nuclear Physics (HITES 2012)

References in corpus (12)

• Solar fusion cross sections II: the pp chain and CNO cycles
• The R-matrix theory
• Ab initio calculation of the Hoyle state
• Structure of A=10-13 nuclei with two- plus three-nucleon interactions from chiral effective field theory
• Nuclear Charge Radii of Be-7,9,10 and the one-neutron halo nucleus Be-11
• Activation measurement of the 3He(alpha,gamma)7Be cross section at low energy
• Nuclear Structure in the Framework of the Unitary Correlation Operator Method
• Astrophysical S-factor of the 3He(alpha,gamma)7Be reaction measured at low energy via prompt and delayed gamma detection
• Microscopic calculation of the 3He(alpha,gamma)7Be and 3H(alpha,gamma)7Li capture cross sections using realistic interactions
• Evidence for Symplectic Symmetry in Ab Initio No-Core Shell Model Results for Light Nuclei
• The 3He + 4He --> 7Be Astrophysical S-factor
• Pair decay width of the Hoyle state and carbon production in stars

Cited by in corpus (13)

• Light nuclei with semilocal momentum-space regularized chiral interactions up to third order
• New applications of renormalization group methods in nuclear physics
• ${}^3\mathrm{He}(\alpha ,\gamma ){}^7\mathrm{Be}$ and ${}^3\mathrm{H}(\alpha ,\gamma ){}^7\mathrm{Li}$ astrophysical $S$ factors from the no-core shell model with continuum
• Ab Initio Description of Open-Shell Nuclei: Merging No-Core Shell Model and In-Medium Similarity Renormalization Group
• Spin-orbit decomposition of ab initio wavefunctions
• Correlated-basis description of $\alpha$-cluster and delocalized $0^{+}$ states in ${}^{16}$O
• Cluster structures in ${}^{12}$C from global energy density functionals
• ${}^{12}$C properties with evolved chiral three-nucleon interactions
• Sensitivities and correlations of nuclear structure observables emerging from chiral interactions
• Evidence of bicluster structure in the ground state of ${}^{20}$Ne
• The Hoyle state and its relatives
• Three-$\alpha$ configurations in the $0^{+}$ states of ${}^{12}\mathrm{C}$
• Harmonic-oscillator excitations of precise few-body wave functions