Giant resonances — experiments at highest resolution, wavelets and scales

Richter, A.

doi:10.1016/j.ppnp.2005.01.002

Cited by 3 publications

(4 citation statements)

References 30 publications

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“…However, the existing measurements were performed using low-resolution gamma-ray detectors. Although the presence of a fine structure superimposed on the broad bump of the ISGQR in 208 Pb has been [32,33]. Different techniques have been used to extract the energy scales associated to the fine structure, [32][33][34][35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

“…Although the presence of a fine structure superimposed on the broad bump of the ISGQR in 208 Pb has been [32,33]. Different techniques have been used to extract the energy scales associated to the fine structure, [32][33][34][35][36][37][38][39]. Comparison with second-RPA calculations indicates that the energy scales can indeed arise from the first step of the damping mechanism, that is the coupling of the 1p-1h states to the 2p-2h states (see e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Comparison with second-RPA calculations indicates that the energy scales can indeed arise from the first step of the damping mechanism, that is the coupling of the 1p-1h states to the 2p-2h states (see e.g. [32,33]). This calls for additional high resolution investigations which are feasible using germanium detectors and also LaBr 3 :Ce scintillator arrays for the gamma decay measurement.…”

Section: Introductionmentioning

confidence: 99%

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Study of the γ decay of high-lying states in²⁰⁸Pb via inelastic scattering of¹⁷O ions

Bracco

Crespi

2012

EPJ Web of Conferences

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Pb by the high resolution measurement of the following gamma decay are also presented in their preliminary form. IntroductionThe use of heavy ions inelastic scattering at approximately 20 MeV/u to study highly excited states (up to the region of the Giant Quadrupole Resonance) is a good tool when the measurement of the subsequent gamma decay is also performed with high resolution. Some partial results of the most recent experiments of this type, performed to investigate the electric-dipole (E1) response of nuclei at energies around the particle threshold, are reported in this contribution. The understanding of the electric-dipole response at energy around the binding energy is presently attracting considerable interest since the dipole strength distribution in that region affects considerably the reaction rates in astrophysical scenarios [1,2], where photodisintegration reactions are important. In addition the E1 strength is also interesting because it is expected to provide information on the neutron skin and thus on the symmetry energy of the equation of state [3][4][5][6][7]. The first evidence of an accumulation of low-lying E1 strength in heavy nuclei, larger than that due to the tail of the giant dipole resonance (GDR), dates back to early 70's [8]. However, only in recent years, experimental and theoretical investigations, on both stable and radioactive nuclei, revealed that this is a common phenomenon in most atomic nuclei [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The accumulation of E1strength around the particle separation energy is commonly denoted as pygmy dipole resonance (PDR) (see e.g.[5]) due to the much smaller size of its strength in comparison with the giant dipole resonance (GDR). The hydrodynamical model describes this pygmy strength as associated to the vibration of the neutron skin. An interesting feature in the region of the pygmy resonance has been observed [25][26][27][28][29] in a number of different stable nuclei, by comparing results of photonscattering and scattering experiments. In particular, it has been found that one group of states is excited in both type of reactions, while another group of states at higher energies is only excited in the ( ') case. These experimental findings are in qualitative agreement with different phonon models which predict a low-lying isoscalar component dominated by neutron-skin oscillations and a higher-lying group of states with a stronger isovector character associated to the tail of the giant dipole resonance. The use of an additional probe as the inelastic scattering of 17 O at 20 MeV/u which has, similarly to alpha particles, a rather strong isoscalar character is expected to add valuable information on the quest of the nature of these low-lying E1 states. In addition, with the same experiment we intended to study of the gamma and neutron decay of the Isoscalar Giant Quadrupole Resonance (ISGQR) in the 10-13 MeV range. In the past, inelastic scattering of 17 O ions at the energy of 22 MeV/u was used to study the gamma deca...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of the γ decay of high-lying states in²⁰⁸Pb via inelastic scattering of¹⁷O ions

Bracco

Crespi

2012

EPJ Web of Conferences

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“…If only "significant" scales are included in this reconstruction, an assessment of their significance can be made [25]. For instance, However, reproduction with scales that would seem to be less significant (A 8 + D 6 + D 2 + D 1 ) leads to much larger errors, as shown in the bottom right-hand panel.…”

Section: E Discrete Wavelet Analysis: Resultsmentioning

confidence: 99%

Analysis of fine structure in the nuclear continuum

et al. 2008

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Fine structure has been shown to be a general phenomenon of nuclear giant resonances of different multipolarities over a wide mass range. In this article we assess various techniques that have been proposed to extract quantitative information from the fine structure in terms of characteristic scales. These include the so-called local scaling dimension, the entropy index method, Fourier analysis, and continuous and discrete wavelet transforms. As an example, results on the isoscalar giant quadrupole resonance in 208 Pb from high-energy-resolution inelastic proton scattering and calculations with the quasiparticle-phonon model are analyzed. Wavelet analysis, both continuous and discrete, of the spectra is shown to be a powerful tool to extract the magnitude and localization of characteristic scales.

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Microscopic description of the low lying and high lying electric dipole strength in stable Ca isotopes

et al. 2007

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Giant resonances — experiments at highest resolution, wavelets and scales

Cited by 3 publications

References 30 publications

Study of the γ decay of high-lying states in²⁰⁸Pb via inelastic scattering of¹⁷O ions

Study of the γ decay of high-lying states in²⁰⁸Pb via inelastic scattering of¹⁷O ions

Analysis of fine structure in the nuclear continuum

Microscopic description of the low lying and high lying electric dipole strength in stable Ca isotopes

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Giant resonances — experiments at highest resolution, wavelets and scales

Cited by 3 publications

References 30 publications

Study of the γ decay of high-lying states in208Pb via inelastic scattering of17O ions

Study of the γ decay of high-lying states in208Pb via inelastic scattering of17O ions

Analysis of fine structure in the nuclear continuum

Microscopic description of the low lying and high lying electric dipole strength in stable Ca isotopes

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Product

Resources

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Study of the γ decay of high-lying states in²⁰⁸Pb via inelastic scattering of¹⁷O ions

Study of the γ decay of high-lying states in²⁰⁸Pb via inelastic scattering of¹⁷O ions