Naslov
Relativistic description of exotic collective excitation phenomena in atomic nuclei

Autori
Paar, Nils ; Nikšić, Tamara ; Vretenar, Dario ; Ring, Peter

Izvornik
International journal of modern physics E (0218-3013) 14 (2005), 1; 29-37

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
random-phase-approximation; hartree-bogoliubov model; rich oxygen isotopes; drip-line nuclei; dipole strength; neutron skin; particle threshold; cross-section; field theory; resonances

Sažetak
The low-lying dipole and quadrupole states in neutron rich nuclei are studied within the fully self-consistent relativistic quasiparticle random-phase approximation (RQRPA), formulated in the canonical basis of the Relativistic Hartree-Bogoliubov model (RHB), which is extended to include the density dependent interactions. In heavier nuclei, the low-lying El excited state is identified as a pygmy dipole resonance (PDR), i.e. as a collective mode of excess neutrons oscillating against a proton-neutron core. Isotopic dependence of the PDR is characterized by a crossing between the PDR and one-neutron separation energies. Already at moderate proton-neutron asymmetry the PDR peak is calculated above the neutron emission threshold, indicating important implications for the observation of the PDR in (gamma, gamma(1)) scattering, and on the theoretical predictions of the radiative neutron capture rates in neutron-rich nuclei. In addition, a novel method is suggested for determining the neutron skin of nuclei, based on measurement of excitation energies of the Gamow-Teller resonance relative to the isobaric analog state.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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