Global Data-Driven Determination of Baryon Transition Form Factors

TL;DR

This paper presents a comprehensive, data-driven analysis of baryon transition form factors, extracting twelve key form factors from extensive electroproduction data, including for higher excited states, advancing understanding of hadronic resonance structures.

Contribution

It introduces a novel simultaneous analysis method for multiple baryon states using large datasets, providing first-time estimates of transition form factors at the poles of higher excited states.

Findings

12 transition form factors extracted at the pole

First estimates for higher excited states' form factors

Qualitative agreement with previous studies for some states

Abstract

Hadronic resonances emerge from strong interactions encoding the dynamics of quarks and gluons. The structure of these resonances can be probed by virtual photons parameterized in transition form factors. In this study, twelve $N^*$ and $\Delta$ transition form factors at the pole are extracted from data with the center-of-mass energy from $\pi N$ threshold to $1.8\,{\rm GeV}$, and the photon virtuality $0\leq Q^2/{\rm GeV}^2\leq 8$. For the first time, these results are determined from a simultaneous analysis of more than one state, i.e., $\sim 10^5$ $\pi N$, $\eta N$, and $K\Lambda$ electroproduction data. In addition, about $ 5\cdot 10^4$ data in the hadronic sector as well as photoproduction serve as boundary conditions. For the $\Delta(1232)$ and $N(1440)$ states our results are in qualitative agreement with previous studies, while the transition form factors at the poles of some higher excited states are estimated for the first time. Realistic uncertainties are determined by further exploring the parameter space.