Temperature and isospin dependence of the level-density parameter in the 
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 mass region

Prajapati, G. K.; Gupta, Y. K.; John, B. V.; Joshi, B. N.; Kaur, Harjeet; Kumar, N. V. Narendra; Danu, L. S.; Mukhopadhyay, S.; Dubey, Shradha; Jain, Sudhir R.; Biswas, D. C.; Nayak, B. K.

doi:10.1103/physrevc.102.054605

“…'s and hence, the disintegration energies to calculate α-decay half-lives. Being non perturbative in nature, these techniques have been employed many times in the past to understand various aspects of nuclear structure viz shell evolution [30,70,75,[88][89][90][91][92][93][94][95][96][97]. From our analysis, we have found that FRDM and our semiclassical method produce disintegration energies of same order.…”

Section: Identification Bymentioning

confidence: 78%

Prediction of half-lives of even–even superheavy nuclei

Pathak

¹

,

Singh

²

,

Kaur

³

et al. 2021

J. Phys. G: Nucl. Part. Phys.

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α-decay half-lives ( T 1 / 2 α -values) of even–even and superheavy nuclei (SHN) are determined employing interaction potential involving Coulomb and proximity potentials. The obtained results are compared with the experimental ones and to assess the precision of the present model in reproducing the experimental half-lives, a comparison is drawn with the other methods as well. We require disintegration energy (Q α -values) as an input in order to predict the ( T 1 / 2 α -values) of an experimentally unknown SHN. So, utilizing periodic-orbit theory within microscopic-macroscopic formalism, we have calculated the binding energies and thereafter, Q α -values of known SHN. The results are found to be in good agreement with the experimental ones. Subsequently, we predict the logarithmic values of T 1 / 2 α ’s for even–even unknown SHN whose atomic numbers lie in 118 ⩽ Z ⩽ 126 regime and compare our results with those calculated employing other theoretical methods. Also, the study of spontaneous fission half-lives and branching ratios leads us to predict the SHN which can be identified through α-decay chains in the laboratories. We believe that this work can play a significant role in the experiments leading to the synthesis and identification of new superheavy elements.

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“…In the statistical reaction and evaporation mechanism (Hauser-Feshbach formalism), the shape of energy spectra of evaporated particle depends on the transmission coefficients (partial widths) and nuclear level densities r [2,61]: p p refer to energies, angular momenta and parities of the compound and residual nuclei, respectively. Also, the fitted Maxwellian distribution of the evaporated charged particle for each incident energy is expressed as follows [48,59]:…”

Section: Statistical Mechanism Of Nuclear Evaporationmentioning

confidence: 99%

“…Initially, based on FGM calculations, it predicted that the NLDP would be purely a mass-dependent and energy-independent parameter. But, using experimental data of low-lying levels, it was shown that this parameter can be affected by many structural effects such as angular momentum [31][32][33], nuclear shell structure [34,35], deformation and collective enhancement [36][37][38][39][40][41], isospin [42][43][44][45] and can be even a function of excitation energy [46][47][48][49]. Therefore, many attempts were made to provide an effective relationship regarding the energy-dependent parameter [50][51][52][53].…”

Section: Introductionmentioning

confidence: 99%

Evidence on the high energy behavior of nuclear level density parameter

Sepiani,

Nasrabadi

2023

Phys. Scr.

0

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The nuclear level density parameter (NLDP) plays an important and crucial role in the most widely used phenomenological models that calculate the nuclear level density (NLD) based on the Fermi gas model (FGM). NLDP can be affected by various effects that have been ignored during the FGM calculations. The dependence of NLDP on excitation energy has been predicted by various references and using various relationships that are mainly tested and normalized at low energies by experimental data of low levels. In this research, using nuclear reaction codes and experimental data of the evaporation spectrum of heavy ion 32S + 74Ge reaction leading to 106Cd compound nucleus (CN) at high excitation energies, high energy behaviour of NLDP is investigated and compared with different relationship predictions. By calculating and reducing the contribution of non-equilibrium mechanisms, it is suggested that NLDP behaves increasing and then decreasing at high energies (almost Gaussian-like behavior), contrary to the predictions of all conventional energy-dependent NLDP relations.

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“…It is well known that the NLD "a" parameter affects the shape of the energy spectra and is often extracted by fitting the simulated spectra onto the experimental data measured at different energies and by separately considering the different particle types [35,36]. However, it is worth noting that this leading parameter, in connection with the moment of inertia (calculated by taking into account the size and shape of emitting nuclei), strongly affects decay cascades by influencing particle emission competition.…”

Section: Differential Multiplicitiesmentioning

confidence: 99%

The New Physics in LILITA_N21: An Improved Description of the Reaction 190 MeV 40Ar + 27Al

Nitto

¹

,

Davide

²

,

Vardaci

³

et al. 2022

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In this paper, light charged particle emission in the evaporation residue channel for the 190 MeV 40Ar + 27Al reaction leading to 67Ga composite nuclei at Ex = 91 MeV and angular momentum up to 46 ℏ has been re-analyzed. The main goal was to study the decay of 67Ga on the basis of an extended set of observables in order to provide a description of the evaporative decay cascades using the multistep Monte Carlo approach. The proton and α-particle energy spectra along with their angular distributions and ratios of differential multiplicities have been considered. The measured observables were compared with statistical model calculations. Having used a single-step Monte Carlo approach and standard parameters decades ago, the model does not provide a good description of the full dataset. Only a subset of the data was reproduced by assuming emitting nuclei with very large deformed shapes in a previous work published in the late 1980s. In the reported analysis, better agreement has been observed. Using the new transmission coefficients from the Optical Model, the parameters of which have recently been derived, the multi-step approach and the introduction of a nuclear shape description based on the nuclear stratosphere allowed us to realize a significant improvement.

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Temperature and isospin dependence of the level-density parameter in the A≈110 mass region

Cited by 10 publications

References 49 publications

Prediction of half-lives of even–even superheavy nuclei

Prediction of half-lives of even–even superheavy nuclei

Evidence on the high energy behavior of nuclear level density parameter

The New Physics in LILITA_N21: An Improved Description of the Reaction 190 MeV 40Ar + 27Al

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