Symmetry Energy in the Semi-empirical Mass Formula

Resonance ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 1567-1578
Author(s):  
Sagnik Mondal ◽  
Pintu Mandal
2019 ◽  
Vol 28 (04) ◽  
pp. 1950022 ◽  
Author(s):  
M. Pal ◽  
S. Chakraborty ◽  
B. Sahoo ◽  
S. Sahoo

An extended nuclear mass formula has been used by considering the bulk, surface and coulomb contributions to the nuclear mass. In this mass formula, the fourth-order symmetry energy coefficient [Formula: see text] of finite nuclei and fourth-order symmetry energy [Formula: see text] of nuclear matter (NM) are related explicitly to the characteristic parameters of NM equation of state (EOS) using finite range effective interaction. The calculations are carried out with Yukawa form of exchange interaction having the same range but with different strengths for interaction between like and unlike nucleon. In this extended mass formula, by approximating [Formula: see text] to a constant [Formula: see text] an explicit relation between [Formula: see text] and fourth-order symmetry energy [Formula: see text] is obtained, which provides the possibility to extract information on [Formula: see text].


1956 ◽  
Vol 6 (2) ◽  
pp. 345-346 ◽  
Author(s):  
G. Szamosi ◽  
M. A. Ziegler
Keyword(s):  

2021 ◽  
Author(s):  
Jose Orce ◽  
Balaram Dey ◽  
Cebo Ngwetsheni ◽  
Brenden Lesch ◽  
Andile Zulu ◽  
...  

Abstract The abundance of heavy elements above iron through the rapid neutron capture process or r-process is intimately related to the competition between neutron capture and $\beta$ decay rates, which ultimately depends on the binding energy of atomic nuclei. The well-known Bethe-Weizsacker semi-empirical mass formula describes the binding energy of ground states in nuclei with temperatures of T~0 MeV, where the nuclear symmetry energy saturates between 23-26 MeV. Here we find a larger saturation energy of ~30 MeV for nuclei at T~0.7-1.3 MeV, which corresponds to the typical temperatures where seed elements are created during the cooling down of the ejecta following neutron-star mergers and collapsars. This large symmetry energy yields a reduction of the binding energy per nucleon for neutron-rich nuclei; hence, the close in of the neutron dripline, where nuclei become unbound. This finding constrains exotic paths in the nucleosynthesis of heavy elements -- as supported by microscopic calculations of radiative neutron-capture rates -- and further supports the universal origin of heavy elements, as inferred from the abundances in extremely metal-poor stars and meteorites.


2018 ◽  
Vol 27 (02) ◽  
pp. 1850015 ◽  
Author(s):  
S. Cht. Mavrodiev ◽  
M. A. Deliyergiyev

We formalized the nuclear mass problem in the inverse problem framework. This approach allows us to infer the underlying model parameters from experimental observation, rather than to predict the observations from the model parameters. The inverse problem was formulated for the numerically generalized semi-empirical mass formula of Bethe and von Weizsäcker. It was solved in a step-by-step way based on the AME2012 nuclear database. The established parametrization describes the measured nuclear masses of 2564 isotopes with a maximum deviation less than 2.6[Formula: see text]MeV, starting from the number of protons and number of neutrons equal to 1.The explicit form of unknown functions in the generalized mass formula was discovered in a step-by-step way using the modified least [Formula: see text] procedure, that realized in the algorithms which were developed by Lubomir Aleksandrov to solve the nonlinear systems of equations via the Gauss–Newton method, lets us to choose the better one between two functions with same [Formula: see text]. In the obtained generalized model, the corrections to the binding energy depend on nine proton (2, 8, 14, 20, 28, 50, 82, 108, 124) and ten neutron (2, 8, 14, 20, 28, 50, 82, 124, 152, 202) magic numbers as well on the asymptotic boundaries of their influence. The obtained results were compared with the predictions of other models.


1962 ◽  
Vol 29 ◽  
pp. 212-240 ◽  
Author(s):  
R. Ayres ◽  
W.F. Hornyak ◽  
L. Chan ◽  
H. Fann
Keyword(s):  

1969 ◽  
Vol 30 (9) ◽  
pp. 607-608 ◽  
Author(s):  
J.R. Rook
Keyword(s):  

2016 ◽  
Vol 1 (2) ◽  
pp. 1-10
Author(s):  
José Pinedo-Vega ◽  
Carlos Ríos-Martínez ◽  
Mirna Talamantes-Carlos ◽  
Fernando Mireles-García ◽  
J Dávila-Rangel ◽  
...  

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