Nucleon Resonance Transition Formfactors

TL;DR

This paper reviews recent CLAS results on nucleon resonance transition form factors, highlighting the interplay of meson-baryon and quark core contributions across different distance scales.

Contribution

It provides experimental data on electromagnetic transition amplitudes and compares them with QCD-based models, emphasizing the role of meson-baryon effects at large distances.

Findings

Meson-baryon contributions are significant at small $Q^2$.

Quark core contributions dominate at large $Q^2$.

Experimental results support QCD-based theoretical models.

Abstract

We discuss recent results from CLAS on electromagnetic resonance transition amplitudes and their dependence on the distance scale ($Q^2$). From the comparison of these results with most advanced theoretical calculations within QCD-based approaches there is clear evidence that meson-baryon contributions are present and important at large distances, i.e. small $Q^2$, and that quark core contributions dominate the short distance behavior.