Search results for "Covariant spectator theory"

showing 3 items of 3 documents

Chiral symmetry and pi-pi scattering in the Covariant Spectator Theory

2014

The pi-pi scattering amplitude calculated with a model for the quark-antiquark interaction in the framework of the Covariant Spectator Theory (CST) is shown to satisfy the Adler zero constraint imposed by chiral symmetry. The CST formalism is established in Minkowski space and our calculations are performed in momentum space. We prove that the axial-vector Ward-Takahashi identity is satisfied by our model. Then we show that, similar to what happens within the Bethe-Salpeter formalism, application of the axial-vector Ward-Takahashi identity to the CST pi-pi scattering amplitude allows us to sum the intermediate quark-quark interactions to all orders. The Adler self-consistency zero for pi-pi…

Chiral symmetryNuclear Theory (nucl-th)High Energy Physics - PhenomenologyCovariant spectator theoryHigh Energy Physics - Phenomenology (hep-ph)Nuclear TheoryHigh Energy Physics::LatticeNuclear TheoryHigh Energy Physics::PhenomenologyQuark-antiquark bound statesFOS: Physical sciences
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Electromagnetic structure of few-nucleon ground states

2015

Experimental form factors of the hydrogen and helium isotopes, extracted from an up-to-date global analysis of cross sections and polarization observables measured in elastic electron scattering from these systems, are compared to predictions obtained in three different theoretical approaches: the first is based on realistic interactions and currents, including relativistic corrections (labeled as the conventional approach); the second relies on a chiral effective field theory description of the strong and electromagnetic interactions in nuclei (labeled $\chi$EFT); the third utilizes a fully relativistic treatment of nuclear dynamics as implemented in the covariant spectator theory (labeled…

QuarkNuclear and High Energy PhysicsParticle physicsNuclear TheoryNuclear TheoryDegrees of freedom (physics and chemistry)FOS: Physical sciencescharge and magnetic radiiElectromagnetic properties01 natural sciences7. Clean energychiral effective field theoryNuclear Theory (nucl-th)Momentum0103 physical sciencesEffective field theoryCovariant transformationNuclear Experiment (nucl-ex)010306 general physicsform factorsNuclear ExperimentIsotopes of heliumPhysics010308 nuclear & particles physicselectric quadrupole and magnetic dipole momentslight nucleiGluoncharge and magnetic radii; chiral effective field theory; covariant spectator theory; electric quadrupole and magnetic dipole moments; form factors; light nuclei; Nuclear and High Energy Physicscovariant spectator theoryFew-nucleon ground statesNucleonJournal of Physics G: Nuclear and Particle Physics
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A covariant constituent-quark formalism for mesons

2014

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 the nonrelativistic bound-state problem in momentum space with a linear confining potential. Although integrable, this kernel has singularities which are difficult to handle numerically. In [2] we reformulate it into a form in which all singularities are explicitely removed. The resulting equations are then easier to solve and yield accurate and stable solutions. In the present work, the same method is applied to the relativistic case, improving upon the r…

PhysicsMesonsIntegrable systemMesonNuclear TheoryNuclear TheoryFOS: Physical sciencesGeneral Physics and AstronomyConstituent quarkPosition and momentum spaceNuclear Theory (nucl-th)High Energy Physics - PhenomenologyCovariant spectator theoryHigh Energy Physics - Phenomenology (hep-ph)SingularityMinkowski spaceCovariant transformationGravitational singularityConfinementMathematical physics
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