Electromagnetic structure of A=2 and 3 nuclei and the nuclear current operator

Journal Article · Fri Jul 01 00:00:00 EDT 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.72.014001· OSTI ID:20698808

Marcucci, L E; Rosati, S ^[1]; Viviani, M; Kievsky, A ^[2]; Schiavilla, R ^[3]

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1. Department of Physics, 'Enrico Fermi', University of Pisa, I-56127 Pisa (Italy)
2. INFN, Sezione di Pisa, I-56100 Pisa (Italy)
3. Department of Physics, Old Dominion University, Norfolk, Virginia 23529 (United States)

Different models for conserved two- and three-body electromagnetic currents are constructed from two- and three-nucleon interactions, using either meson-exchange mechanisms or minimal substitution in the momentum dependence of these interactions. The connection between these two different schemes is elucidated. A number of low-energy electronuclear observables, including (i) np radiative capture at thermal neutron energies and deuteron photodisintegration at low energies, (ii) nd and pd radiative capture reactions, and (iii) isoscalar and isovector magnetic form factors of {sup 3}H and {sup 3}He, are calculated to make a comparative study of these models for the current operator. The realistic Argonne v{sub 18} two-nucleon and Urbana IX or Tucson-Melbourne three-nucleon interactions are taken as a case study. For A=3 processes, the bound and continuum wave functions, both below and above deuteron breakup threshold, are obtained with the correlated hyperspherical harmonics method. Three-body currents give small but significant contributions to some of the polarization observables in the {sup 2}H(p,{gamma}){sup 3}He process and the {sup 2}H(n,{gamma}){sup 3}H cross section at thermal neutron energies. It is shown that the use of a current that did not exactly satisfy current conservation with the two- and three-nucleon interactions in the Hamiltonian was responsible for some of the discrepancies reported in previous studies between the experimental and theoretical polarization observables in pd radiative capture.

• OSTI ID: 20698808
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 72, Issue 1; Other Information: DOI: 10.1103/PhysRevC.72.014001; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALGEBRAIC CURRENTS
BOSON-EXCHANGE MODELS
CAPTURE
CROSS SECTIONS
DEUTERIUM
DEUTERONS
ELECTROMAGNETIC FORM FACTORS
HAMILTONIANS
HELIUM 3
NUCLEAR FORCES
PHOTONUCLEAR REACTIONS
POLARIZATION
PROTONS
THERMAL NEUTRONS
THREE-BODY PROBLEM
TRITIUM
TRITONS
WAVE FUNCTIONS