Speaker
Description
Experimental investigations of the structure of excited nucleon states ($N^*$s) from different exclusive channels in terms of their $\gamma_vpN^*$ electrocouplings over a broad range of $Q^2$ are providing essential insights into the nature of the non-perturbative strong interaction responsible for their generation. Extraction of electrocouplings from analyses of $\pi N$, $\eta N$, and $\pi\pi N$ data from CLAS at JLab have been completed for most $N^*$ states up to 1.8~GeV and $Q^2 < 5$~GeV$^2$ with electron beams up to 6~GeV. Recent analyses of these results within QCD-connected approaches and quark models have shown remarkable agreement with data, leading to improved insights into the dynamical origins for the emergent part of hadron mass. New experiments with CLAS12 at beam energies up to 11~GeV extend $Q^2$ to $\approx$10~GeV$^2$, which will allow for the exploration of strong interaction dynamics at distance scales where the transition between quark-gluon confinement and pQCD is expected. Further advances in understanding $N^*$ structure, especially for states above 1.8~GeV, will rely on data from the $KY$ exclusive channels from CLAS and CLAS12 since some $N^*$s decay preferentially to $\pi \pi N$ final states. The $KY$ data are necessary to provide independent cross-checks for the extracted electrocouplings to those from other channels. In this regard, development of reaction models for $KY$ electroproduction are of particular importance. This presentation will highlight results from ongoing analyses of $KY$ final states from CLAS12 data. Future studies at a possible 22~GeV energy-upgraded JLab are also now being considered to approach the pQCD regime with studies of exclusive processes and will be discussed.
