Covariant Spectator Theory of np scattering: Isoscalar interaction currents

Abstract

Using the Covariant Spectator Theory (CST), one boson exchange (OBE) models have been found that give precision fits to low energy np scattering and the deuteron binding energy. The boson-nucleon vertices used in these models contain a momentum dependence that requires a new class of interaction currents for use with electromagnetic interactions. Current conservation requires that these new interaction currents satisfy a two-body Ward-Takahashi identity, and using principals of simplicity and picture independence, these currents can be uniquely determined. The results lead to general formulae for a two-body current that can be expressed in terms of relativistic np wave functions, Psi, and two convenient truncated wave functions, ${\Psi }^{(2)}$ and $\hat{\Psi }$, which contain all of the information needed for the explicit evaluation of the contributions from the interaction current. These three wave functions can be calculated from the CST bound or scattering state equations (and their off-shell extrapolations). A companion paper uses this formalism to evaluate the deuteron magnetic moment.

arXiv comment25 pages, 10 figures

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Cited by in corpus (6)

• Electromagnetic Structure of Few-Nucleon Ground States
• Covariant Spectator Theory of $np$ scattering: Deuteron form factors
• Covariant Spectator Theory of np scattering: Deuteron magnetic moment and form factors
• Representations of relativistic particles of arbitrary spin in Poincaré, Lorentz, and Euclidean covariant formulations of relativistic quantum mechanics
• Covariant Spectator Theory of np scattering: Deuteron Quadrupole Moment
• Removal of singularities from the covariant spectator theory