Isospin dependence of the nucleon density distributions

2017 ◽  
Vol 26 (10) ◽  
pp. 1750065
Author(s):  
Yongli Xu ◽  
Hairui Guo ◽  
Yinlu Han ◽  
Qingbiao Shen
Keyword(s):  
Experimental Data ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Nucleon Density ◽  
Charge Radii ◽  
Density Distributions ◽  
Neutron Skin Thickness ◽  
Isospin Dependence ◽  
Two Parameter ◽  
Good Agreement

The nucleon density distributions were usually described by the two-parameter Fermi shape formula. In this work, the isospin effects in the nucleon density distributions are considered, and a three-parameter formula is proposed and modified by simultaneously considering the experimental data of 885 root-mean-square (rms) charge radii and neutron skin thickness of 26 stable nuclei. The improved nucleon density formula is physically reasonable and achieves a good agreement for the charge radii and neutron skin thickness calculated with the new nucleon density formula comparing the available experimental data.

NEUTRON SKIN THICKNESS IN NEUTRON-RICH NUCLEI: BULK AND SURFACE CONTRIBUTIONS AND SHELL EFFECTS

2012 ◽  
Vol 21 (05) ◽  
pp. 1250029 ◽  
Author(s):  
X. VIÑAS ◽  
M. WARDA ◽  
M. CENTELLES ◽  
X. ROCA-MAZA
Keyword(s):  
Mean Field ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Isotopic Chain ◽  
Effective Interactions ◽  
Shell Effects ◽  
Mean Field Models ◽  
Neutron Skin Thickness ◽  
Field Approaches ◽  
Two Parameter

We analyze theoretically the neutron skin thickness in nuclei and its correlation with the symmetry energy by using semiclassical and mean field approaches together with nuclear effective interactions. Semiclassical approaches reveal that the neutron skin thickness in nuclei is formed by a combination of bulk and surface contributions. To investigate the neutron skin thickness predicted by mean field models, we fit the corresponding densities by two-parameter Fermi distributions. Using these parametrized densities, we study the neutron skin thickness as well as its bulk and surface contributions in 208 Pb and in Zr isotopes, where the influence of shell effects along the isotopic chain is discussed.

ISOSPIN EFFECT AND ISOSCALING PHENOMENON IN PROJECTILE FRAGMENTATION

2008 ◽  
Vol 17 (09) ◽  
pp. 1669-1680 ◽  
Author(s):  
C. W. MA ◽  
Y. FU ◽  
D. Q. FANG ◽  
Y. G. MA ◽  
X. Z. CAI ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Projectile Fragmentation ◽  
Skin Thickness ◽  
Neutron Density ◽  
Neutron Skin ◽  
Density Distributions ◽  
Neutron Rich Nucleus ◽  
Neutron Skin Thickness ◽  
Neutron Density Distribution ◽  
The Relationship

We have studied the isospin effect and isoscaling behavior in projectile fragmentation using a modified statistical abrasion-ablation (SAA) model. The relationship between neutron skin thickness (δnp) and neutron abrasion cross section (σ nabr ) has also been investigated. We find the normalized peak differences and reduced isoscaling parameters decrease with (Z proj - Z)/Z proj or the excitation energy per nucleon and have no significant dependence on the size of the reaction systems. The excitation energy dependence of the symmetry energy coefficients are tentatively extracted from α and β. Assuming Fermi-type density distributions for proton and neutron and introducing a parameter to adjust the diffuseness of the neutron density distribution for neutron-rich nucleus, δnp and σ nabr for neutron-rich nucleus were found to have a linear correlation. It is suggested that σ nabr could be used as an observable to extract the neutron skin thickness for neutron-rich nucleus.

scholarly journals Investigation of density and form factor of some F isotopes using Hartree-Fock and shell model calculations

2019 ◽  
Vol 14 (30) ◽  
pp. 158-171
Author(s):  
Wasan Z. Majeed
Keyword(s):  
Shell Model ◽  
Electron Scattering ◽  
Form Factors ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Model Calculations ◽  
Hartree Fock ◽  
Density Distributions ◽  
Tail Part ◽  
Good Agreement

Structure of unstable 21,23,25,26F nuclei have been investigatedusing Hartree – Fock (HF) and shell model calculations. The groundstate proton, neutron and matter density distributions, root meansquare (rms) radii and neutron skin thickness of these isotopes arestudied. Shell model calculations are performed using SDBAinteraction. In HF method the selected effective nuclear interactions,namely the Skyrme parameterizations SLy4, Skeσ, SkBsk9 andSkxs25 are used. Also, the elastic electron scattering form factors ofthese isotopes are studied. The calculated form factors in HFcalculations show many diffraction minima in contrary to shellmodel, which predicts less diffraction minima. The long tailbehaviour in nuclear density is noticeable seen in HF more than shellmodel calculations. The deviation occurs between shell model andHF results are attributed to the sensitivity of charge form factors tothe change of the tail part of the charge density. Calculations donefor the rms radii in shell model showed excellent agreement withexperimental values, while HF results showed an overestimation inthe calculated rms radii for 21,23F and good agreement for 25,26F. Ingeneral, it is found that the shell model and HF results have the samebehaviour when the mass number (A) increase.

INVESTIGATIONS OF THE DENSITY DISTRIBUTIONS OF 208Pb WITH THE THOMAS–FERMI METHOD

2013 ◽  
Vol 28 (23) ◽  
pp. 1350108 ◽  
Author(s):  
M. GOKBULUT ◽  
H. KOC ◽  
E. ESER ◽  
I. YIGITOGLU ◽  
B. A. MAMEDOV
Keyword(s):  
Experimental Data ◽  
The Other ◽  
Proton Density ◽  
Nucleon Density ◽  
Analytical Expression ◽  
Thomas Fermi ◽  
Density Distributions ◽  
Good Agreement

In this study, the neutron and proton density distributions of 208 Pb nucleus have been analytically calculated by using a new, simple and physically meaningful analytical expression obtained for the Fermi integral which is situated in the nucleon density distributions. The results obtained for 208 Pb have been compared with those of the other theoretical and experimental data and found in good agreement.

Formation of α clusters in dilute neutron-rich matter

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. 260-264 ◽  
Author(s):  
Junki Tanaka ◽  
Zaihong Yang ◽  
Stefan Typel ◽  
Satoshi Adachi ◽  
Shiwei Bai ◽  
...  
Keyword(s):  
Cross Sections ◽  
Cluster Formation ◽  
Reaction Cross ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Heavy Nuclei ◽  
Α Decay ◽  
Neutron Skin Thickness ◽  
Reaction Cross Sections ◽  
Α Particles

The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster–knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.

Dependence of n/p with neutron skin thickness for neutron-rich nuclei

2010 ◽  
Vol 834 (1-4) ◽  
pp. 502c-504c ◽  
Author(s):  
X.Y. Sun ◽  
D.Q. Fang ◽  
Y.G. Ma ◽  
X.Z. Cai ◽  
X.G. Cao ◽  
...  
Keyword(s):  
Skin Thickness ◽  
Neutron Skin ◽  
Neutron Skin Thickness
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