Structure and evolution of electric dipole strength in 204,206,208Pb below the neutron emission threshold

Enders, J.; Brentano, P. von; Eberth, J.; Fitzler, A.; Fransen, C.; Herzberg, R.‐D.; Kaiser, H.; Käubler, L.; Neumann-Cosel, P. von; Pietralla, N.; Ponomarev, V. Yu.; Prade, H.; Richter, A.; Schnare, H.; Schwengner, R.; Skoda, S.; Thomas, H. G.; Tiesler, H.; Weißhaar, D.; Wiedenhöver, I.

doi:10.1016/s0370-2693(00)00730-9

Cited by 41 publications

(14 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further studies [5][6][7] reveal fine structures in the RSF, which are commonly called pygmy resonances. This name does not refer to specific structures: the E1 pygmy resonance in the E γ = 5 − 7 MeV region of gold to lead nuclei could be due to neutron skin oscillations [8], whereas bumps in the 3 MeV region of rare earth nuclei are now determined to be of M1 character [9,10]. The electromagnetic character and measured strength of the latter pygmy resonance is compatible with the scissors mode.…”

Section: Introductionmentioning

confidence: 99%

Radiative strength functions inMo93−98

et al. 2005

View full text Add to dashboard Cite

Radiative strength functions (RSFs) in 93−98 Mo have been extracted using the ( 3 He,αγ) and ( 3 He, 3 He ′ γ) reactions. The RSFs are U-shaped as function of γ energy with a minimum at around Eγ = 3 MeV. The minimum values increase with neutron number due to the increase in the lowenergy tail of the giant electric dipole resonance with nuclear deformation. The unexpected strong increase in strength below Eγ = 3 MeV, here called soft pole, is established for all 93−98 Mo isotopes. The soft pole is present at all initial excitation energies in the 5 − 8 MeV region.

show abstract

Section: Introductionmentioning

confidence: 99%

Radiative strength functions inMo93−98

et al. 2005

View full text Add to dashboard Cite

show abstract

“…For the (E1, E1) and the (M 1, M 1) sequences, i.e., for equal parities of the initial and final state, the situation is more complex and it is more difficult to draw conclusions from simple relations similar to Eqs. (6)(7)(8)(9). In general, one can state that in these cases, the calculated TSC intensities will be higher for E1 than for M 1 multipolarity of the soft dipole mode under study, but the differences between the two calculations are smaller than in the case of opposite parities of the initial and final state.…”

Section: Character Of Soft Dipole Modesmentioning

confidence: 92%

“…This model suggest a quite strong PR which is not supported by experimental data. However, recently some indications in (γ, γ ′ ) experiments for the existence of a weak E1 PR in lead nuclei have been discussed [7]. On the other hand, the hypothesis has been suggested [8] that the PR observed at E γ ∼ 3.0 MeV in the quasicontinuous γ spectra of well-deformed rare-earth nuclei and the so-called 'scissors mode' excitation studied by the nuclear resonance fluorescence method (NRF) [9] have the same physical origin.…”

Section: Introductionmentioning

confidence: 99%

Determination of the electromagnetic character of soft dipole modes solely based on quasicontinuous γ spectroscopy

Voinov

Schiller

Guttormsen

et al. 2003

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

We show that the combined analysis of the quasicontinuous γ spectra from the ( 3 He,α) and the (n th , 2γ) reactions gives the possibility to measure the electromagnetic character of soft dipole resonances. Two-step γ-cascade spectra have been calculated, using level densities and radiative strength functions from the ( 3 He,αγ) reaction. The calculations show that the intensity of the twostep cascades depends on the electromagnetic character of the soft dipole resonance under study. The difference reaches 40-100% which can be measured experimentally. PACS number(s): 25.20.Lj, 24.30.Gd

show abstract

“…Experiments exploring Coulomb excitation, and polarized proton scattering off neutron-rich nuclei to extract the dipole polarizability and its relation to the slope parameter have been reported in a several publications in Refs. [129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148], just to cite a few of them. To date, there is a large variation in the measurements of α D in the order of 20-30%.…”

Section: Dipole Polarizabilitymentioning

confidence: 99%

Pygmy resonances and symmetry energy

Bertulani

2019

Eur. Phys. J. A

View full text Add to dashboard Cite

I present a brief summary of the first three decades of studies of pygmy resonances in nuclei and their relation to the symmetry energy of nuclear matter. I discuss the first experiments and theories dedicated to study the electromagnetic response in halo nuclei and how a low energy peak was initially identified as a candidate for the pygmy resonance. This is followed by the description of a collective state in medium heavy and heavy nuclei which was definitely identified as a pygmy resonance. The role of the slope parameter of the symmetry energy in determining the properties of neutron stars is stressed. The theoretical and experimental information collected on pygmy resonances, neutron skins, and the numerous correlations found with the slope parameter is briefly reviewed. PACS. 25.20.-x Photonuclear reactions -26.60.+c Nuclear matter aspects of neutron starsTo the memory of Pier Francesco Bortignon

show abstract

Structure and evolution of electric dipole strength in 204,206,208Pb below the neutron emission threshold

Cited by 41 publications

References 35 publications

Radiative strength functions inMo93−98

Radiative strength functions inMo93−98

Determination of the electromagnetic character of soft dipole modes solely based on quasicontinuous γ spectroscopy

Pygmy resonances and symmetry energy

Contact Info

Product

Resources

About