عنوان البحث(Papers / Research Title)
Dipole and Quadrupole Electroexcitations of the Isovector T = 1 Particle-Hole States in C-12
الناشر \ المحرر \ الكاتب (Author / Editor / Publisher)
فؤاد عطية مجيد
Citation Information
فؤاد,عطية,مجيد ,Dipole and Quadrupole Electroexcitations of the Isovector T = 1 Particle-Hole States in C-12 , Time 5/2/2011 8:09:56 PM : كلية التربية للعلوم الصرفة
وصف الابستركت (Abstract)
shell model calculations in the framewrok of particel-hole configuration.
الوصف الكامل (Full Abstract)
Dipole and Quadrupole Electroexcitations of the Isovector T = 1 Particle-Hole States in 12C
Abstract:
Electroexcitations of the dominantly T = 1 particle-hole states of 12C are studied in the framework of the harmonic oscillator shell model. All possible T = 1 single-particle-hole states of all allowed angular momenta are considered in a basis including single-particle states up to the 1f-2p shell. The Hamiltonian is diagnoalized in this space in the presence of the modified surface delta interaction. Correlation in the ground state wave functions by mixing more than one configuration is considered and shows a major contribution that leads to enhance the calculations of the form factors. A comparison with the experiment shows that this model is able to fit the location of states and a
simple scaling of the results give a good fit to the experimental form factors.
Introduction
Nuclear structure models can be successfully tested by comparing the calculated and measured electron scattering form factors. The success of such a model reveals a valuable information about the charge and current distributions of nuclei. The transverse electric form factor of the 2+ level a 16.107 MeV T = 1 of 12C were measured by Flanz et al.,[1] by means of 180? electron scattering over a momentum-transfer range from q=0.51 to 2.05 fm?1. Deutschmann et al.,[2] studied the inelastic electron scattering cross section for the M1 transition to the 15.11 MeV (1+,T = 1) level and for M2 transition to the 16.58 MeV (2?,T = 1) level in 12C in the momentum-transfer region (q=0.4–3.0 fm?1). Electron scattering at 200 MeV on 12C and 13C, have been studied by T. Sato et al., [3] to investigate magnetic dipole M1 and electric quadrupole E2 nuclear form factors. The effect of higher configurations wave functions are investigated by Bennhold et al., [4]. Donnelly [5] studied the T = 1 single-particle-hole states of 12C on the basis of the harmonic oscillator (HO) shell model in the particle-hole formalism developed by Lewis and Walecka, configuration mixing is included via a Serber–Yukawa residual interaction.
In this Letter, we study the isovector (T = 1) transition in 12C which connects the (J =0+, T=0) ground state with the (J =2?, 3? and 3+) isovector states. The ground state is taken to have closed 1s1/2 and 1p1/2 shells. The states expected to be most strongly excited from closed-shell nuclei are linearly combination of a configurations
in which one nucleon has been raised to a higher shell, forming pure single-particle-hole state [6].
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This work is published in (Chinese Physics Letters)
F. A. Majeed and R. A. Radhi 2006 Chinese Phys. Lett. 23 2699 doi: 10.1088/0256-307X/23/10/021
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