Comments on Baryon Transition Form Factors

TL;DR

This paper examines the complex nature of space-like baryon transition form factors, emphasizing the importance of phase motion and illustrating these concepts with Roper resonance form factors.

Contribution

It clarifies why baryon transition form factors are complex and highlights potential pitfalls of assuming they are real, with analysis based on the Jülich-Bonn-Washington framework.

Findings

Transition form factors are inherently complex-valued.

Real-valued assumptions can lead to misleading interpretations.

Illustration using Roper resonance form factors.

Abstract

We discuss in rather general terms the properties of space-like baryon transition form factors. In particular, we argue why these are necessarily complex-valued, what can be deduced from the respective phase motion and why dealing with real valued transition form factors in general leads to misleading results. For illustration the transition form factors for the Roper resonance as derived in the J\"ulich-Bonn-Washington framework are discussed.