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A Poincare' covariant Faddeev equation is presented, which enables the simultaneous prediction of meson and baryon observables using the leading-order in a truncation of the Dyson-Schwinger equations that can systematically be improved. The…

Nuclear Theory · Physics 2010-04-15 G. Eichmann , I. C. Cloet , R. Alkofer , A. Krassnigg , C. D. Roberts

A dressed-quark core contribution to nucleon electromagnetic form factors is calculated. It is defined by the solution of a Poincare' covariant Faddeev equation in which dressed-quarks provide the elementary degree of freedom and…

Nuclear Theory · Physics 2010-03-04 I. C. Cloet , G. Eichmann , B. El-Bennich , T. Klahn , C. D. Roberts

Established results for the quark propagator in Landau gauge QCD, together with a detailed comparison to lattice data, are used to formulate a Poincare covariant Faddeev approach to the nucleon. The resultant three-quark amplitudes describe…

High Energy Physics - Phenomenology · Physics 2009-12-15 G. Eichmann , A. Krassnigg , M. Schwinzerl , R. Alkofer

We recently reported new results on the $\gamma^{(*)} + N(940)\frac{1}{2}^+ \to \Delta(1700)\frac{3}{2}^{-}$ transition form factors using a symmetry-preserving treatment of a vector$\,\otimes\,$vector contact interaction (SCI) within a…

High Energy Physics - Phenomenology · Physics 2025-05-27 L. Albino , G. Paredes-Torres , K. Raya , A. Bashir , J. Segovia

We develop a formally covariant quark-diquark model of the nucleon. The nucleon is treated as a bound state of a constituent quark and a diquark interacting via a quark exchange. We include both scalar and axial-vector diquarks. The…

Nuclear Theory · Physics 2007-05-23 Volker Keiner

The electromagnetic form factors of the nucleon are calculated in an extended chiral constituent-quark model where the effective interaction is described by the exchange of pseudoscalar, vector, and scalar mesons. Two-body current-density…

High Energy Physics - Phenomenology · Physics 2007-05-23 P. Demetriou , S. Boffi , M. Radici , R. F. Wagenbrunn

High-precision nucleon-resonance electroproduction data on a large kinematic domain of energy and momentum transfer have proven crucial in revealing novel features of strong interactions within the Standard Model and unfolding structural…

Nuclear Theory · Physics 2019-02-27 Chen Chen , Ya Lu , Daniele Binosi , Craig D. Roberts , Jose Rodríguez-Quintero , Jorge Segovia

We compute nucleon and Roper e.m. elastic and transition form factors using a symmetry-preserving treatment of a contact-interaction. Obtained thereby, the e.m. interactions of baryons are typically described by hard form factors. In…

Nuclear Theory · Physics 2015-06-03 D. J. Wilson , I. C. Cloet , L. Chang , C. D. Roberts

We provide details on a recent solution of the nucleon's covariant Faddeev equation in an explicit three-quark approach. The full Poincare-covariant structure of the three-quark amplitude is implemented through an orthogonal basis obtained…

High Energy Physics - Phenomenology · Physics 2010-04-30 G. Eichmann , R. Alkofer , A. Krassnigg , D. Nicmorus

We study the N-Delta-gamma transition in the Dyson-Schwinger approach. The nucleon and Delta baryons are treated as quark-diquark bound states, where the ingredients of the electromagnetic transition current are computed self-consistently…

High Energy Physics - Phenomenology · Physics 2013-05-30 Gernot Eichmann , Diana Nicmorus

Electromagnetic form factors of the nucleon in the space-like region are investigated within the framework of a covariant and confining Nambu-Jona-Lasinio model. The bound state amplitude of the nucleon is obtained as the solution of a…

Nuclear Theory · Physics 2014-10-15 Ian C. Cloët , Wolfgang Bentz , Anthony W. Thomas

Some short history of few-body methods originated from the famous Skornyakov-Ter-Martirosyan equation is given, including latest development of Faddeev formalism and Efimov states. The 3q system is shown to require an alternative, which is…

High Energy Physics - Phenomenology · Physics 2014-11-17 Yu. A. Simonov

An important goal of ongoing and future experiments is to explore spectra and transition form factors of baryons with non-zero strangeness. Of particular interest is the transition form factor$\gamma^{(*)} \Sigma^0 \rightarrow \Lambda$ in…

High Energy Physics - Phenomenology · Physics 2024-04-16 Langtian Liu , Christian S. Fischer

$K_{\ell 3}$ and $\pi_{e 3}$ transition form factors are calculated as an application of Dyson-Schwinger equations. The role of nonanalytic contributions to the quark--W-boson vertex is elucidated. A one-parameter model for this vertex…

Nuclear Theory · Physics 2010-03-04 Yu. Kalinovsky , K. L. Mitchell , C. D. Roberts

We derive light-cone sum rules for the electromagnetic nucleon form factors including the next-to-leading-order corrections for the contribution of twist-three and twist-four operators and a consistent treatment of the nucleon mass…

High Energy Physics - Phenomenology · Physics 2013-12-16 I. V. Anikin , V. M. Braun , N. Offen

A valuable approach to the analysis of hadron physics observables is provided by QCD's equations-of-motion; namely, the Dyson-Schwinger equations. Drawing from a diverse collection of predictions, we revisit: $\gamma \gamma^* \to$ neutral…

Nuclear Theory · Physics 2019-12-12 Khépani Raya , Lei Chang , Minghui Ding , Daniele Binosi , Craig D. Roberts

Working with a Poincar\'e-covariant quark + diquark, $q(qq)$, Faddeev equation approach to nucleon structure, a refined symmetry preserving current for electron + nucleon elastic scattering is developed. The parameters in the interaction…

High Energy Physics - Phenomenology · Physics 2025-07-21 Peng Cheng , Zhao Qian Yao , Daniele Binosi , Ya Lu , Craig D. Roberts

Nucleon form factors are calculated in a relativistic diquark--quark picture based on the Nambu--Jona-Lasinio model. The nucleon wave function is obtained in a static approximation to the quark exchange interaction between the valence quark…

High Energy Physics - Phenomenology · Physics 2016-09-01 G. Hellstern , C. Weiss

We study electromagnetic properties of the nucleon and Roper resonance in a chiral quark-diquark model including two kinds of diquarks needed to describe the nucleon: scalar and axial-vector diquarks. The nucleon and Roper resonance are…

High Energy Physics - Phenomenology · Physics 2007-08-28 Keitaro Nagata , Atsushi Hosaka

A new, more efficient approach to include a three nucleon force into three-nucleon continuum calculations is presented. Results obtained in the new and our old approach are compared both for elastic nucleon-deuteron scattering as well as…

Nuclear Theory · Physics 2007-05-23 D. Hüber , H. Kamada , H. Witała , W. Glöckle