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Related papers: A Covariant model for the nucleon and the $\Delta$

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Results for the proton and neutron electric and magnetic form factors as well as the nucleon axial form factor are presented for constituent quark models, based on either one-gluon-exchange and Goldstone-boson-exchange dynamics. The…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. F. Wagenbrunn , S. Boffi , L. Ya. Glozman , W. Klink , W. Plessas , M. Radici

In Poincar\'e-covariant continuum treatments of the three valence-quark bound-state problem, the force behind dynamical chiral symmetry breaking also generates nonpointlike, interacting diquark correlations in the nucleon and its…

Nuclear Theory · Physics 2016-11-09 Jorge Segovia , Craig D. Roberts

The electromagnetic form factors of the Delta baryon are evaluated within the framework of a covariant spectator quark model, where S and D-states are included in the $\Delta$ wave function. We predict all the four Delta multipole form…

High Energy Physics - Phenomenology · Physics 2014-11-20 G. Ramalho , M. T. Pena , Franz Gross

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…

Nuclear Theory · Physics 2008-05-05 T. Melde , K. Berger , L. Canton , W. Plessas , R. F. Wagenbrunn

We propose a new model of the nucleon in which quark-diquark configurations immersed in a pion cloud are treated in a manner consistent with Poincar\'e invariance. With suitably chosen parameters, the computations employing this model…

Nuclear Theory · Physics 2013-05-30 Ian C. Cloet , Gerald A. Miller

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…

Nuclear Theory · Physics 2010-04-06 Sérgio Alexandre Pinto , Alfred Stadler , Franz Gross

In this talk, the electromagnetic transition form factors from the nucleon ground state to twelve $N^*$ and $\Delta$ states are exhibited and discussed. Those results are extracted through a comprehensive coupled-channel approach -- the…

Nuclear Theory · Physics 2026-01-29 Yu-Fei Wang

Addressing the recent criticisms of Kvinikhidze and Miller, we prove that the spectator wave functions and currents based on ``fixed-axis'' polarization states (previously introduced by us) are Lorentz covariant, and find an explicit…

Nuclear Theory · Physics 2009-11-13 Franz Gross , G. Ramalho , M. T. Pena

The study of electromagnetic and weak form factors of nucleon (charged quasielastic scatterings of neutrino (antineutrino) and nucleon) done in $70^\prime s$ and published in Chinese journals is reviewed. In the approach of the study…

High Energy Physics - Phenomenology · Physics 2014-11-25 Bing An Li

Using the covariant spectator theory (CST), we present the results of a valence quark-diquark model calculation of the nucleon structure function f(x) measured in unpolarized deep inelastic scattering (DIS), and the structure functions…

High Energy Physics - Phenomenology · Physics 2012-05-24 Franz Gross , G. Ramalho , M. T. Pena

The electromagnetic form factors of the nucleon have been calculated in a chiral constituent-quark model. The nucleon wave functions are obtained by solving a Schr\"odinger-type equation for a semi-relativistic Hamiltonian with an effective…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. Boffi , P. Demetriou , M. Radici , R. F. Wagenbrunn

A parameter-free evaluation of the $N - \Delta$ electromagnetic transition form factors is carried out in a light-front constituent quark model, based on $N$ and $\Delta$ eigenstates of a mass operator which reproduces a large set of hadron…

Nuclear Theory · Physics 2009-10-28 F. Cardarelli , E. Pace , G. Salme' , S. Simula

We present an alternative parameterization of the quark-diquark model of baryons which particularly takes care of the most recent proton electric form-factor data from the E136 experiment at SLAC. In addition to electromagnetic form factors…

High Energy Physics - Phenomenology · Physics 2009-10-22 R. Jakob , P. Kroll , M. Schuermann , W. Schweiger

In the covariant quark-diquark model the effective Bethe-Salpeter (BS) equations for the nucleon and the $\Delta$ are solved including scalar {\em and axialvector} diquark correlations. Their quark substructure is effectively taken into…

Nuclear Theory · Physics 2008-11-26 M. Oettel , R. Alkofer , L. von Smekal

We present a study of proton and neutron electromagnetic form factors for the recently proposed Goldstone-boson-exchange constituent quark model. Results for charge radii, magnetic moments, and electric as well as magnetic form factors are…

Nuclear Theory · Physics 2009-11-06 R. F. Wagenbrunn , S. Boffi , W. Klink , W. Plessas , M. Radici

Using a covariant spectator quark model that describes the recent lattice QCD data for the $\Delta$ electromagnetic form factors and all available experimental data on $\gamma N \to \Delta$ transitions, we analyze the charge and magnetic…

Nuclear Theory · Physics 2012-11-22 G. Ramalho , M. T. Pena , A. Stadler

Point-form relativistic quantum mechanics is applied to elastic electron-deuteron scattering. The deuteron is modeled using relativistic interactions that are scattering-equivalent to the nonrelativistic Argonne $v_{18}$ and Reid '93…

Nuclear Theory · Physics 2011-07-19 T. W. Allen , W. H. Klink , W. N. Polyzou

The nucleon axial vector form factor is investigated in a light-cone quark spectator diquark model, in which Melosh rotations are applied to both the quark and vector diquark. It is found that this model gives a very good description of…

High Energy Physics - Phenomenology · Physics 2009-11-07 Bo-Qiang Ma , Di Qing , Ivan Schmidt

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…

Nuclear Theory · Physics 2009-06-30 Sérgio Alexandre Pinto , Alfred Stadler , Franz Gross

We calculate magnetic moments of nucleons and hyperons and N -> Delta + gamma transition characteristics using a manifestly Lorentz covariant chiral quark approach for the study of baryons as bound states of constituent quarks dressed by a…

High Energy Physics - Phenomenology · Physics 2007-11-15 Amand Faessler , Thomas Gutsche , Barry R. Holstein , Valery E. Lyubovitskij , Diana Nicmorus , Kem Pumsa-ard