相关论文: Spectator theory for three-nucleon electromagnetic…
We derive relativistic three-dimensional integral equations describing the interaction of the three-nucleon system with an external electromagnetic field. Our equations are unitary, gauge invariant, and they conserve charge. This has been…
The electromagnetic form factors of the three-nucleon bound states were calculated in Complete Impulse Approximation in the framework of the Covariant Spectator Theory for the new high-precision two-nucleon interaction models WJC-1 and…
We derive a complete Feynman diagram expansion for the elastic form factor and the three-body photo and electrodisintegration of the three-body bound state using the covariant spectator theory. We show that the equations obtained are fully…
We present the first calculations of the electromagnetic form factors of $^3$He and $^3$H within the framework of the Covariant Spectator Theory (CST). This first exploratory study concentrates on the sensitivity of the form factors to the…
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…
A constituent quark model based on the spectator formalism is applied to the gamma N -> N* transition for the three cases, where N* is the nucleon, the Delta and the Roper resonance. The model is covariant, and therefore can be used for the…
The covariant spectator formalism is used to model the nucleon and the $\Delta$(1232) as a system of three constituent quarks with their own electromagnetic structure. The definition of the ``fixed-axis'' polarization states for the diquark…
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…
We present a study of the electromagnetic structure of the nucleons with constituent quark models in the framework of relativistic quantum mechanics. In particular, we address the construction of spectator-model currents in the instant and…
The relativistic constituent quark model of low-energy quantum chromodynamics is found to yield a consistent picture of the electroweak structure of the nucleons. Notably, the electromagnetic and axial form factors of both the proton and…
We present a general derivation the three-body spectator (Gross) equations and the corresponding electromagnetic currents. As in previous paper on two-body systems, the wave equations and currents are derived from those for Bethe-Salpeter…
We show that all four of the nucleon form factors can be very well explained using the manifestly covariant spectator theory. The nucleon is modeled as a spherical state of three constituent quarks with electromagnetic form factors, all…
Using the framework of the Covariant Spectator Theory (CST) [1] we are developing a covariant model formulated in Minkowski space to study mesonic structure and spectra. Treating mesons as effective $q\bar{q}$ states, we focused in [2] on…
We address the construction of transition operators for electromagnetic, weak, and hadronic reactions of relativistic few-quark systems along the spectator model. While the problem is of relevance for all forms of relativistic quantum…
Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator…
Recent progress in Lorentz-covariant quantum field theories of the nuclear many-body problem (quantum hadrodynamics or QHD) is discussed. The effective field theory studied here contains nucleons, pions, isoscalar scalar (\sigma) and vector…
Nucleon structure functions, as measured in deep-inelastic lepton scattering, are studied within a covariant scalar diquark spectator model. Regarding the nucleon as an approximate two-body bound state of a quark and diquark, the…
A big spectrum of processes induced by real and virtual photons on the 3He and 3H nuclei is theoretically investigated through many examples based on nonrelativistic Faddeev calculations for bound and continuum states. The modern…
Recent progress in Lorentz-covariant quantum field theories of the nuclear many-body problem (quantum hadrodynamics or QHD) is discussed. The effective field theory studied here contains nucleons, pions, isoscalar scalar (\sigma) and vector…
Recently, we have shown that the continuity equation for the nuclear vector and axial current operators acquires additional terms if the latter depend on the energy transfer. We analyze in detail the electromagnetic single-nucleon…