Structure of the pygmy dipole resonance in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>124</mml:mn></mml:msup></mml:math>Sn

Endres, J.; Savran, D.; Butler, P. A.; Harakeh, Mohsen; Harissopulos, S.; Herzberg, R.‐D.; Krücken, R.; Lagoyannis, A.; Литвинова, Елена; Pietralla, N.; Ponomarev, V. Yu.; Popescu, L.; Ring, P.; Scheck, M.; Schlüter, Felix; Sonnabend, K.; Stoica, Victor; Wörtche, H. J.; Zilges, A.

doi:10.1103/physrevc.85.064331

Cited by 61 publications

(54 citation statements)

References 48 publications

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“…This observation is a clear indication for a change of structure in the low-lying E1 strength. The same pattern has been observed in 94 Mo [26], 124 Sn [27,28], and 138 Ba [29]. Figure 2 provides an overview of the data, showing the comparison of the results of the corresponding (α, α γ) and (γ, γ ) experiments for each nucleus.…”

Section: Results From Hadron Scatteringmentioning

confidence: 58%

Experimental results on the Pygmy Dipole Resonance

Savran

2014

EPJ Web of Conferences

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Section: Results From Hadron Scatteringmentioning

confidence: 58%

Experimental results on the Pygmy Dipole Resonance

Savran

2014

EPJ Web of Conferences

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“…Combined (γ, γ ) and (α, α γ) experiments on the open shell 124 Sn [11,12,28] found that the low-lying dipole strength splits into an upper sector composed of isovector transitions promoted by γ's and a lower region of levels populated by both α's and γ's. Only these low-lying peaks form therefore the PDR.…”

Section: Calculations and Resultsmentioning

confidence: 99%

“…In stable nuclei, dense discrete spectra of dipole states were detected in (γ, γ ) [3][4][5][6][7][8][9] and in (α, α γ) experiments [10][11][12]. Moreover, fairly complete dipole spectra below and above the neutron decay threshold were produced with great accuracy through inelastic proton scattering experiments [13,14].…”

Section: Introductionmentioning

confidence: 90%

Dipole response in neutron-rich nuclei within self-consistent approaches using realistic potentials

Iudice

Knapp

Veselý

et al. 2015

EPJ Web of Conferences

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Abstract.A nucleon-nucleon chiral potential with a corrective density dependent term simulating a three-body force is used in a self-consistent calculation of the dipole strength distribution in neutron-rich nuclei, with special attention to the low-lying spectra associated to the pygmy resonance. A Hartree-Fock-Bogoliubov basis is generated and adopted in Tamm-Dancoff and random-phase approximations and, then, in an equation of motion approach which includes a basis of two-phonon states. The direct use of the mentioned chiral potential improves the description of both giant and pygmy dipole modes with respect to other realistic interactions. Moreover, the inclusion of the two-phonon states induces a pronounced fragmentation of the giant resonance and enhances the density of the low-lying levels in the pygmy region in agreement with recent experiments.

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“…This prediction seems to be disproved by the isoscalarisovector splitting observed in (α, α ′ γ) experiments on open shell nuclei like 140 Ce [15] and 124 Sn [5,16,17]. For a conclusive test, it would be of great help to perform an analogous experiment on the stable doubly magic 208 Pb.…”

Section: Empmmentioning

confidence: 99%

“…Radioactive beam experiments have extracted an appreciable dipole strength just above the neutron decay threshold in unstable nuclei, like neutron rich oxygen [3] or tin isotopes around 132 Sn [4]. More detailed data were obtained for stable nuclei by combining (γ, γ ′ ) [5][6][7][8][9][10][11][12][13][14] with (α, α ′ γ) measurements [15][16][17][18] which have detected rich low lying spectra of weakly excited discrete levels below the neutron threshold over different mass regions.…”

Section: Introductionmentioning

confidence: 99%

Dipole response inPb208within a self-consistent multiphonon approach

et al. 2015

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Background: The electric dipole strength detected around the particle threshold and commonly associated to the pygmy dipole resonance offers a unique information on neutron skin and symmetry energy, and is of astrophysical interest. The nature of such a resonance is still under debate.Purpose: We intend to describe the giant and pygmy resonances in 208 Pb by enhancing their fragmentation with respect to the random-phase approximation. Method:We adopt the equation of motion phonon method to perform a fully self-consistent calculation in a space spanned by one-phonon and two-phonon basis states using an optimized chiral two-body potential. A phenomenological density dependent term, derived from a contact three-body force, is added in order to get single-particle spectra more realistic than the ones obtained by using the chiral potential only. The calculation takes into full account the Pauli principle and is free of spurious center of mass admixtures. Results:We obtain a fair description of the giant resonance and obtain a dense low-lying spectrum in qualitative agreement with the experimental data. The transition densities as well as the phonon and particle-hole composition of the most strongly excited states support the pygmy nature of the low-lying resonance. Finally, we obtain realistic values for the dipole polarizability and the neutron skin radius. Conclusions:The results emphasize the role of the two-phonon states in enhancing the fragmentation of the strength in the giant resonance region and at low energy, consistently with experiments. For a more detailed agreement with the data, the calculation suggests the inclusion of the three-phonon states as well as a fine tuning of the single-particle spectrum to be obtained by a refinement of the nuclear potential.

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Structure of the pygmy dipole resonance in124Sn

Cited by 61 publications

References 48 publications

Experimental results on the Pygmy Dipole Resonance

Experimental results on the Pygmy Dipole Resonance

Dipole response in neutron-rich nuclei within self-consistent approaches using realistic potentials

Dipole response inPb208within a self-consistent multiphonon approach

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