Four-body correlations in nuclei

Abstract

Low-energy spectra of 4$n$ nuclei are described with high accuracy in terms of four-body correlated structures ("quartets"). The states of all $N\ge Z$ nuclei belonging to the $A=24$ isobaric chain are represented as a superposition of two-quartet states, with quartets being characterized by isospin $T$ and angular momentum $J$. These quartets are assumed to be those describing the lowest states in ${}^{20}$Ne ($T_z$=0), ${}^{20}$F ($T_z$=1) and ${}^{20}$O ($T_z$=2). We find that the spectrum of the self-conjugate nucleus ${}^{24}$Mg can be well reproduced in terms of $T$=0 quartets only and that, among these, the $J$=0 quartet plays by far the leading role in the structure of the ground state. The same conclusion is drawn in the case of the three-quartet $N=Z$ nucleus ${}^{28}$Si. As an application of the quartet formalism to nuclei not confined to the $sd$ shell, we provide a description of the low-lying spectrum of the proton-rich ${}^{92}$Pd. The results achieved indicate that, in 4$n$ nuclei, four-body degrees of freedom are more important and more general than usually expected.

5 pages, 4 figures

References in corpus (4)

• Evidence for a spin-aligned neutron-proton paired phase from the level structure of ${}^{92}$Pd
• Isoscalar and isovector pairing in a formalism of quartets
• Isovector proton-neutron pairing and Wigner energy in Hartree-Fock mean field calculations
• Isovector pairing in a formalism of quartets for N=Z nuclei

Cited by in corpus (15)

• Shape coexistence in even-even nuclei: A theoretical overview
• A quartet BCS-like theory
• Isoscalar-isovector proton-neutron pairing and quartet condensation in N=Z nuclei
• Cooper quartet correlations in infinite symmetric nuclear matter
• Quartet correlations in N=Z nuclei induced by realistic two-body interactions
• Quartetting in odd-odd self-conjugate nuclei
• Band-like structures and quartets in deformed N=Z nuclei
• Pairing correlations and eigenvalues of two-body density matrix in atomic nuclei
• Disentangling the pair and quartet condensates
• Exact T=0 Eigenstates of the Isovector Pairing Hamiltonian
• Unified description of pairing and quarteting correlations within the particle-hole-boson approach
• Quartet structure of $N=Z$ nuclei in a boson formalism: the case of ${}^{28}$Si
• Structure of the quartetting ground state of $N=Z$ nuclei
• Coexistence of quartets and pairs in even-even $N>Z$ nuclei
• Quartet condensation induced by the isovector pairing force