New soft mode in the 11Li nucleus excited through (p,p′) reaction

Fayans, S.A.; Ershov, S. N.; Svinareva, E.F.

doi:10.1016/0370-2693(92)91168-9

Cited by 11 publications

(3 citation statements)

References 14 publications

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“…This resonance can be understood as a novel pygmy monopole mode due to the soft incompressibility of loosely-bound neutron skin or halo, while the incompressibility of low density nuclear matter has not been well understood. The experimental study of low-energy monopole modes in unstable nuclei is feasible with specially arranged detectors around zero degrees [40,41].…”

Section: Fig 2 (Color Online)mentioning

confidence: 99%

Emergent soft monopole modes in weakly bound deformed nuclei

Pei

Kortelainen²,

Zhang³

et al. 2014

Phys. Rev. C

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Based on the Hartree-Fock-Bogoliubov solutions in large deformed coordinate spaces, the finite amplitude method for the quasiparticle random-phase approximation (FAM-QRPA) has been implemented, providing a suitable approach to probing collective excitations of weakly bound nuclei embedded in the continuum. The monopole excitation modes in magnesium isotopes up to the neutron drip line have been studied with the FAM-QRPA framework on both the coordinate-space and harmonic oscillator basis methods. Enhanced soft monopole strengths and collectivity as a result of weak-binding effects have been unambiguously demonstrated. Nuclei close to the particle drip lines are weakly bound superfluid quantum systems and can exhibit exotic threshold phenomena [1], sharing interdisciplinary interests with weakly bound systems such as multiquark states, Rydberg atoms, and quantum droplets [1][2][3]. Since the discovery of nuclear halos with radioactive beams [4], there have been numerous theo retical developments aiming at weakly bound nuclei and their dilute surfaces [5], Extensive Hartree-Fock-Bogoliubov (HFB) studies have provided successful descriptions of continuum couplings and halo features in ground states of weakly bound nuclei [6][7][8][9][10][11][12]. On the other hand, excitations in weakly bound nuclei opened vast possibilities to probing novel collective modes, as well as continuum effects and components of the effective interaction that are suppressed in ground states [13][14][15], To address these issues, along with the operation of forthcoming facilities such as the Facility for Rare Isotope Beams (FRIB) at Michigan State University, an accurate and self-consistent treatment of continuum together with pairing correlations, deformations, and large spatial extensions is essential.Among the excited states in weakly bound nuclei, the emergent soft excitation modes (or pygmy resonances) which correspond to the collective motion between neutron halo/skins and cores are particularly intriguing. These modes can impact astrophysical neutron capture rates and r-process nucleosynthesis. However, the collectivity of observed pygmy resonances, as a crucial verification of coherence, is still under debate [13,14,16], This Rapid Communication is devoted to the low-energy monopole excitations in weakly bound nuclei caused by the soft incompressibility of halos, as the dilute nuclear matter has a decreased incompressibility compared to saturated densities [17], The low-energy monopole modes indeed have been predicted, e.g., in the neutron-rich nickel isotopes (observed very recently in 68Ni [ 18]), as a rather non collective excitation [19]; however, it may hardly be expected in another random-phase approximation (RPA) calculation with a proper treatment of continuum [20]. Besides, the collectivity could be enhanced due to weak-binding effects [15], Therefore, the emergence of collective soft monopole modes, as well as the role of continuum contributions with the fully self-consistent continuum quasiparticle randomphase approximati...

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Section: Fig 2 (Color Online)mentioning

confidence: 99%

Emergent soft monopole modes in weakly bound deformed nuclei

Pei

Kortelainen²,

Zhang³

et al. 2014

Phys. Rev. C

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“…From the presence of a halo in 6He some features associated with the exotic nuclei have been expected, in particular the possible appearance of collective states similar to giant resonances but at much lower energies than in normal nuclei [6,7]. Particular interest was sparked off by the prediction [8] of a soft-dipole mode in nuclei with two weakly bound valence neutrons which may have been observed [91 in "Li at excitation energy about 1 MeV.…”

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confidence: 99%

Direct Experimental Evidence for a Soft-Dipole Response in ⁶ He

et al. 1993

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“…For exotic nuclei with a large neutron excess, a soft monopole mode may emerge, which brings new insights into the nuclear incompressibility and has become the goals for both experimental and theoretical investigations. For instance, it has been observed experimentally in 11 Li [32] and 68 Ni [33], and is predicted in the neutronrich magnesium [34], calcium [35], nickel [25], tin [36], and lead [36] isotopes. However, for heavy and deformed exotic nuclei, the structure and mechanism of the soft monopole mode are not clear.…”

Section: Introductionmentioning

confidence: 99%

Finite amplitude method on the deformed relativistic Hartree-Bogoliubov theory in continuum: The isoscalar giant monopole resonance in exotic nuclei

Sun,

Meng

2022

Preprint

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Finite amplitude method based on the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc-FAM) is developed and applied to study isoscalar giant monopole resonance in exotic nuclei. Validation of the numerical implementation is examined for 208 Pb. The isoscalar giant monopole resonances for even-even calcium isotopes from 40 Ca to the last bound neutron-rich nucleus 80 Ca are calculated, and a good agreement with the available experimental centroid energies is obtained for 40−48 Ca. For the exotic calcium isotopes, e.g., 68 Ca and 80 Ca, the DRHBc-FAM calculated results are closer to the energy weighted sum rule than the calculations on the harmonic oscillator basis, which highlights the advantages of DRHBc-FAM in describing giant resonances for exotic nuclei. In order to explore the soft monopole mode in the exotic nuclei, the giant monopole resonance for the deformed exotic nucleus 200 Nd is investigated, where the prolate shape and the oblate shape coexist. A soft monopole mode near 6.0 MeV is found in the prolate case, and another one near 4.5 MeV is found in the oblate case. The transition density of the soft monopole mode shows in phase or out-of-phase vibrations near the surface region, which is generated by quadrupole vibrations.

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New soft mode in the 11Li nucleus excited through (p,p′) reaction

Cited by 11 publications

References 14 publications

Emergent soft monopole modes in weakly bound deformed nuclei

Emergent soft monopole modes in weakly bound deformed nuclei

Direct Experimental Evidence for a Soft-Dipole Response in ⁶ He

Finite amplitude method on the deformed relativistic Hartree-Bogoliubov theory in continuum: The isoscalar giant monopole resonance in exotic nuclei

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New soft mode in the 11Li nucleus excited through (p,p′) reaction

Cited by 11 publications

References 14 publications

Emergent soft monopole modes in weakly bound deformed nuclei

Emergent soft monopole modes in weakly bound deformed nuclei

Direct Experimental Evidence for a Soft-Dipole Response in 6 He

Finite amplitude method on the deformed relativistic Hartree-Bogoliubov theory in continuum: The isoscalar giant monopole resonance in exotic nuclei

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Direct Experimental Evidence for a Soft-Dipole Response in ⁶ He