Role of the extended model-space with M3Y-core polarization interaction on the electron scattering form factors for 19F

Other Title(s)

دور أنموذج الفضاء الموسع مع تفاعل (M3Y)‎ المستخدم في استقطاب القلب على عوامل التشكل للاستطارة الإلكترونية لنواة 19F

Dissertant

Fattah, Aziz Hama Rahim

Thesis advisor

Radi, Rad Abd al-Karim
Abd Allah, Ali Atiyyah

Comitee Members

Mansur, Hazim L.
Chiad, Baha T.
Salih, Muhammad A. B.
Hammudi, Adil Khalaf
Adib, Nadiyah Muhammad

University

University of Baghdad

Faculty

College of Science

Department

Department of Physics

University Country

Iraq

Degree

Ph.D.

Degree Date

2009

English Abstract

Nuclear structure of 19F was studied by the elastic and inelastic electron scattering to measure the form factors and transition rates for the low-lying levels over the momentum transfers between The electron scattering charge and current multipole operators was expanded in a second quantized fermion representation for applying shell-model technique with the extended model-spaces starting from the core shell model to the no-core shell model.

The radial wave functions for the single-particle matrix elements were calculated by the harmonic oscillator (HO) potential where the oscillator length parameter b = 1.833 fm was chosen to reproduce the measured root mean square charge radius. The calculations are performed with different model spaces wave functions including core-polarization effects.

The core-polarization effects on the form factor are based on microscopic theory, which combines shell model wave functions and configurations with higher energy as first order perturbation.

The realistic two-body Michigan three range Yukawa (M3Y) interaction was proposed to calculate core-polarization matrix elements, which was applied for the inert-core nuclei 16O, 12C, and 4He corresponding to the model spaces sd, (Zuker-Buck-McGrory)ZBM, and psd respectively. The form factors for the positive-parity states, ?? ? 1⁄2? , 3⁄2? , 5⁄2? , 7⁄2? , 9⁄2? were determined due to the core-nuclei 16O, and 4He for 2??-excitation calculations; while the core-nuclei 4He and 12C were used to evaluate the form factors due to the negative-parity states , ?? ? 5⁄2? ? , 5⁄2? ? , 7⁄2? ? , 7⁄2? ? for the 1??- excitation calculations. Another part of this work represents the large-basis no core shell-model calculations, at which a large no core model space will be adopted for a model space (spsdpf) to cover the four major shells 1s, 1p, 2s–1d, 2p–1f to study and calculate elastic and inelastic electron scattering form factors with XII their corresponding reduced transition probabilities.

By taking into consideration a ?0 ? 2??ω truncated no core calculation for the excitations of types ?1? ? 1?? and ?2? ? 2??. In both cases, the effective charges for the protons and neutrons were calculated successfully and the theoretical form factors were compared with the experimental data, which was found to be in a good agreement especially for the Coulomb form factors. Chapter one Introduction 1 1.1: Introduction Electron scattering from nuclei [1-8], provides us with an invaluable tool to probe the wide variety of nuclear and nucleonic properties, because it has proven itself as one of the most effective methods of studying the properties of the energy levels of atomic nuclei, so it has provided a wealth of information, mapping out nuclear ground state charge densities and precise transition charge and current densities for the excitation of single particle states and for collective states [9-10]. Electron scattering offers a variety of advantages for the study of nuclear structure and the electrons as a probe of nuclear structure have a special place in the study of nuclear structure [11].

This is because the interaction of electrons with nucleons, the electromagnetic interaction, is well known and relatively weak compared with the nuclear interaction that is hardly perturbs the nucleus under the investigation, structure constant ( ? ? ??⁄?? ? 1⁄137? .

Hence, in practice electron scattering can be described with sufficient accuracy in the Distorted Wave Born Approximation (DWBA), the ability to vary independently the momentum and energy transferred to the nucleus, as well as excellent spatial resolution that can be obtained with the point-like probing particles, have made this approach a valuable tool in nuclear physics[12]. Since electrons are charged and light, they by necessity radiate during the scattering process.

This is one of the technical complications of electron scattering.

This radiation as well as the accompanying virtual electromagnetic effects are described by quantum electrodynamics (QED).In electron scattering experiments where the momentum of the initial and final electron are well-defined, the produced virtual quantum of electromagnetic radiation interacts with the targe

Main Subjects

Physics

No. of Pages

156

Table of Contents

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Language

English

Data Type

Arab Theses

Record ID

BIM-598345