Extension of the random phase approximation including the self-consistent coupling to two-phonon contributions
Articolo
Data di Pubblicazione:
2003
Citazione:
Extension of the random phase approximation including the self-consistent coupling to two-phonon contributions / C. Barbieri, W.H. Dickhoff. - In: PHYSICAL REVIEW. C, NUCLEAR PHYSICS. - ISSN 0556-2813. - 68:1(2003), pp. 014311.1-014311.14.
Abstract:
A microscopic formalism is developed that includes the coupling to two particle-hole phonons in the particle-hole propagator by extending the dressed random phase approximation (DRPA) equation for a finite system. The resulting formalism is applied to study the low-lying excitation spectrum of [Formula Presented] It is observed that the coupling to two-phonon states at low energy generates excited states with quantum numbers that cannot be obtained in the DRPA approach. Nevertheless, the two-phonon states mix weakly with particle-hole configurations and participate only partially in the formation of the lowest-lying positive-parity excited states. The stability of the present calculation is tested vs the truncation of model space. It is demonstrated that when single-particle strength fragmentation is properly considered, the present formalism exhibits convergence with respect to the chosen model space within the confines of the chosen approximation scheme.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
interacting boson model; spectroscopic factors; range correlations; resonant states; finite nuclei; O-16; energy; O-16(E,E’P); expansions; momentum
Elenco autori:
C. Barbieri, W.H. Dickhoff
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