Recent results on the nucleon resonance spectrum and structure from the CLAS detector

TL;DR

This paper reviews recent experimental results from the CLAS detector on nucleon resonances, highlighting new insights into hadron structure, transition amplitudes, and evidence for a new baryon state, advancing understanding of quantum chromodynamics.

Contribution

It presents new measurements of nucleon resonance transition amplitudes and provides evidence for a previously unobserved baryon state, enhancing the understanding of hadron structure.

Findings

Access to the dressed quark mass function through combined analysis.

New transition amplitudes for N* resonances from CLAS data.

Evidence for a new baryon state N'(1720)3/2+.

Abstract

The CLAS detector at Jefferson Lab has provided the dominant part of all available worldwide data on exclusive meson electroproduction off protons in the resonance region. New results on the $\gamma_{v}pN^*$ transition amplitudes (electrocouplings) are available from analyses of the CLAS data and will be presented. Their impact on understanding of hadron structure will be discussed emphasizing the credible access to the dressed quark mass function that has been achieved for the first time by a combined analysis of the experimental results on the electromagnetic nucleon elastic and $N \rightarrow N^*$ transition form factors. We will also discuss further convincing evidences for a new baryon state $N^{\, '}(1720)3/2^+$ found in a combined analysis of charged double pion photo- and electroproduction cross sections off the protons.