Advanced parametrisations for hadronic form factors

TL;DR

This paper introduces two new parametrisations for hadronic form factors that incorporate complex analytic features like resonance poles and cuts, improving the theoretical modeling of these quantities.

Contribution

The paper presents novel parametrisations that explicitly include resonance poles and left-hand cuts, enhancing the analytic description of hadronic form factors.

Findings

Enables study of resonance poles on the second Riemann sheet

Connects form factors to partial-wave amplitudes

Improves analytic consistency of parametrisations

Abstract

The rich analytic structure of hadronic form factors makes a theoretically consistent yet easily applicable parametrisation cumbersome. Consequently, most parametrisations are limited to reproducing the simplest analytic features sufficient to describe form factors on their first Riemann sheet. Here, we introduce two novel form factor parametrisations that allow resonance poles and left-hand cuts on the second Riemann sheet to be studied, while also making the connection to partial-wave amplitudes manifest.