Jorge Segovia

Argonne National Laboratory, Argonne, IL

Nucleon and Delta Elastic and Transition Form Factors


The elastic and transition form factors involving the nucleon and its resonances provide a unique window into their quark and gluon structure; giving distinctive information on the roles played by confinement and dynamical chiral symmetry breaking in Quantum Chromodynamics (QCD). The QCD Dyson-Schwinger equations (DSEs) have been established as a tool capable of relating these emergent phenomena with experimental observables. We will present a unified study of nucleon and delta elastic and transition form factors, and compare predictions made using a framework built upon a Faddeev equation kernel and interaction vertices that possess QCD-like momentum dependence with results obtained using a symmetry-preserving treatment of a vector x vector contact-interaction. The comparison emphasises that experiments are sensitive to the momentum dependence of the running couplings and masses in the strong interaction sector of the Standard Model and highlights that the key to describing hadron properties is a veracious expression of dynamical chiral symmetry breaking in the bound-state problem. Our analysis and predictions should therefore serve as motivation for measurement of elastic and transition form factors of nucleon excited states at high photon virtualities using modern electron-beam facilities.


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