Backward pion-nucleon scattering

TL;DR

This paper presents a Regge model analysis of backward pion-nucleon scattering data above 3 GeV, successfully reproducing angular and polarization data and providing evidence for a baryon resonance at 2.83 GeV.

Contribution

It introduces a comprehensive Regge model including multiple trajectories to analyze backward pion-nucleon scattering and identifies a new baryon resonance below 3 GeV.

Findings

Reproduces angular distributions and polarization data for small Mandelstam u values.

Provides evidence for a G_{39} baryon resonance at 2.83 GeV.

Suggests the G_{39} resonance as part of the Δ_{β} trajectory.

Abstract

A global analysis of the world data on differential cross sections and polarization asymmetries of backward pion-nucleon scattering for invariant collision energies above 3 GeV is performed in a Regge model. Including the $N_\alpha$, $N_\gamma$, $\Delta_\delta$ and $\Delta_\beta$ trajectories, we reproduce both angular distributions and polarization data for small values of the Mandelstam variable $u$, in contrast to previous analyses. The model amplitude is used to obtain evidence for baryon resonances with mass below 3 GeV. Our analysis suggests a $G_{39}$ resonance with a mass of 2.83 GeV as member of the $\Delta_{\beta}$ trajectory from the corresponding Chew-Frautschi plot.