Nuclear level densities with blocking effect

Benzi, V.; Maino, G.; Menapace, E.

doi:10.1007/bf02724615

Cited by 17 publications

(4 citation statements)

References 15 publications

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“…The first feature is that, although the odd particle is allowed to distribute in all the levels in the exact diagonalization of the pairing Hamiltonian, it always occupies the fifth level, which is the highest occupied one. This feature invalidates the conventional assumption given in the Maino's method [102,103] that the odd particle must be on any level above the Fermi surface. The Maino's method was popularly used to describe the pairing properties of excited odd nuclei.…”

Section: Finite-temperature Pairing Reentrance In Odd Nucleimentioning

confidence: 82%

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Pairing in excited nuclei: a review

2019

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The present review summarizes the recent studies on the thermodynamic properties of pairing in many-body systems including superconductors, metallic nanosized clusters and/or grains, solid-state materials, focusing on the excited nuclei, that is nuclei at finite temperature and/ or angular momentum formed via heavy-ion fusion, α-induced fusion reactions, or inelastic scattering of light particles on heavy targets. Because of the finiteness of the systems, several interesting effects of pairing such as nonvanishing pairing gap, smoothing of superfluidnormal phase transition, first and second order phase transitions, pairing reentrance, etc, will be discussed in detail. Influences of exact and approximate thermal pairing on some nuclear properties such as temperature-dependent width of the giant dipole resonance, total level density, and radiative strength function of the γ-rays emission will be also analyzed. Finally, the first experimental evidence of the pairing reentrance phenomenon in a 104 Pd nucleus as well as its solid-state counterpart of ferromagnets under strong magnetic field will be presented.

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Section: Finite-temperature Pairing Reentrance In Odd Nucleimentioning

confidence: 82%

“…under the assumption that the phonon operators ( 101) are ideal boson ones, that is [Q ν , Q † ν ] = δ νν , which, together with the quasiboson approximation (103), leads to the normalization condition…”

Section: Role Of Pairing In Properties Of Excited Nucleimentioning

confidence: 99%

Pairing in excited nuclei: a review

2019

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“…If experiments have missed levels of a particular parity at a few MeV, the parity ratio will not approach 1/2 as the energy increases. For heavy nuclei [14,15], positive and negative parity states are expected to become equal already at low excitation energy to the order of a few MeV, while in lighter spherical nuclei stronger shell effects keep the ratio ρ (π = +) / ρ (π = -) considerably different from unity over a wider energy range [16,17].…”

Section: Parity Ratio Analysismentioning

confidence: 99%

Parity dependence of Nuclear Level Density

Badola¹,

Singhal²,

Bhatnagar³

2018

IJSRPAS

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The knowledge parity dependent nuclear level density (E, J, π) is very essential in low energy nuclear physics as it is used to evaluate nuclear cross-sections in nuclear reaction calculations. At low excitation energies, astrophysical reaction rates are sensitive to the parity distribution. However, the information of level density is confined to a rather small region of excitation energy, angular momentum and parity. Several theoretical studies have shown that at low energies there is a dominance of one type of parity and near the particle separation energy that parity ratio only approaches to an equal distribution. An accurate determination of nuclear level density and its dependence on mass number, excitation energy, angular momentum, parity, etc. is necessary for precise prediction of cross sections using the statistical models. In the present work, an absolute asymmetry parameter is used to determine the level density of negative as well as for positive parity states by using sand p-wave (D 0 and D 1 ) neutron level spacing. The systematic are investigated from 23 < A < 238 and compared to the pattern found in previous investigations. The present analysis also provides useful information on various resonance parameters at different nuclear mass regions with results that support the original conclusions.

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“…At finite temperature, the same assumption was considered, and the thermal properties are calculated using statistical average of all possible blocked level above the Fermi level. 48,49 Under this consideration, the calculations were performed in the framework of the FTBCS method.…”

Section: Introductionmentioning

confidence: 99%

Pairing phase transition in ^106,107,108Pd

Kadi

Benhamouda

2015

Int. J. Mod. Phys. E

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The pairing phase transition is investigated in hot even-even and even-odd P d isotopes such as 106 ≤ A ≤ 108 in a framework of a microscopic approach that takes into account the statistical fluctuations. In this aim, one considers the Modified BCS method (MBCS). The latter is extended to the odd system case, where the blocking effect is included. The model was applied to the evaluation of the thermal properties such as the excitation energy, entropy and heat capacity. The obtained results are compared on one hand to the usual finite temperature BCS (FTBCS) method and on the other hand to the experimental data. The obtained results allow to show that the thermal fluctuations smooth out the superfluid-normal (SN) phase transition observed in the usual FTBCS results. Moreover, in the region where the pairing phase transition occurs, the experimental data of thermal properties are better reproduced when statistical fluctuations are considered in MBCS method instead of the FTBCS approach.

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Nuclear level densities with blocking effect

Cited by 17 publications

References 15 publications

Pairing in excited nuclei: a review

Pairing in excited nuclei: a review

Parity dependence of Nuclear Level Density

Pairing phase transition in ^106,107,108Pd

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Nuclear level densities with blocking effect

Cited by 17 publications

References 15 publications

Pairing in excited nuclei: a review

Pairing in excited nuclei: a review

Parity dependence of Nuclear Level Density

Pairing phase transition in 106,107,108Pd

Contact Info

Product

Resources

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Pairing phase transition in ^106,107,108Pd