Matter density distribution and elastic electron scattering form factors of some exotic nuclei

Other Title(s)

توزيع كثافة المادة و عوامل التشكل للاستطارة الإلكترونية المرنة لبعض النوى الغريبة

Dissertant

Majid, Wasan Zuhayr

Thesis advisor

Radi, Rad Abd al-Karim
Hammudi, Adil Khalaf

University

University of Baghdad

Faculty

College of Science

Department

Department of Physics

University Country

Iraq

Degree

Ph.D.

Degree Date

2013

English Abstract

Results of the ground state proton, neutron and matter density distributions and the corresponding root mean square (rms) radii of unstable two- neutron halo 6He, 11Li, 12Be and 14Be nuclei and oneproton halo 8B nucleus are obtained within the two- frequency shell model (TFSM) approach.

Also, the elastic electron scattering form factors of these exotic nuclei are studied through Plane Wave Born Approximation (PWBA) and compared to those of stable isotopes in the same isotopic chain.

In the description of the halo nuclei it is important to take into account a model space for core nuclei different from the halo neutrons (proton) which have to be treated separately in order to explain their properties.

In the present work, a core nuclei have the following configurations, (1s1/2 )4 are used for 4He, (1s1/2 )4, (1p3/2 )5 for 9Li, (1s1/2 )4, (1p )6 for 10Be, (1s1/2 )4, (1p )8 for 12Be and (1s1/2 )4, (1p3/2 )3 for 7Be.

The description of the two halo neutrons in 6He is described by the configuration mixing of the psd orbits, while for the two neutrons in 11Li, we use the 1p1/2 ,1d5/2, 2s1/2 model space, with Mcgrory- Wildenthal interaction.

The two halo neutrons in 12Be and 14Be was described by the configuration mixing of the sd orbits with universal shell model (USD).

For 8B, one configuration is assumed for the outer proton to be in 1p1/2- shell.

The results of the matter density distributions are compared with those of the fitted to the experimental data.

The long tail behavior, considered as a distinctive feature of halo nuclei, is evidently revealed in the calculated density distributions of nuclei under study.

Besides, the noticeable different is found between the calculated over all proton and neutron rms radii of these nuclei which also indicates a halo structure.

Abstract III The structures of the halo 6He, 11Li and 8B nuclei show that the dominant configurations when the two halo neutrons of 6He, 11Li and one halo proton of 8B distributed over the 1p shell orbits while 12Be and 14Be nuclei have a (1d)- dominant configuration.

For neutron-rich nuclei (6He, 11Li, 12Be, 14Be), it is found that the form factor is not dependent on detailed properties of the neutron halo.

Only the difference in the center of mass correction which depends on the mass number and the size parameter b which is assumed in this case equal to the average of bcore and bhalo and the difference is attributed to the difference in the recoil effect.

While the difference between the calculated charge form factors of proton–rich nucleus 8B with the stable isotope 10B is attributed to the influence of the charge density distributions of the last proton in 8B and the difference in the center of mass correction.

The results show that the electron scattering will be very useful and important in studying both neutron-and proton–rich nuclei in the future.

The present results can provide predictions for elastic electron scattering from exotic nuclei in the near future experiments on the electron-radioactive beam colliders, where the effect of the neutron halo or skin on the charge distributions is planned to be studied.

Main Subjects

Physics

No. of Pages

99

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-608115