Measurement of the reaction $\gamma p \rightarrow K^ + \Sigma^{\pm}\pi^{\mp}$ at photon energies up to 2.6 GeV

TL;DR

This study measures the cross sections of specific photon-induced reactions producing hyperons and pions, revealing resonant state production and energy-dependent behavior up to 2.6 GeV with improved data quality.

Contribution

It provides new, high-statistics measurements of reaction cross sections and resonance production in gamma-proton interactions up to 2.6 GeV, improving upon previous data.

Findings

Cross sections increase monotonously with photon energy.

Resonant states are substantially produced in the reactions.

Enhanced statistical accuracy compared to previous measurements.

Abstract

The reactions $\gamma p \rightarrow K^{+}\Sigma^{\pm}\pi^{\mp}$ were studied with the SAPHIR detector using a tagged photon beam at the electron stretcher facility ELSA in Bonn. The decays $\Sigma^{-} \rightarrow n\pi^{-}$ and $\Sigma^{+} \rightarrow n\pi^{+}, p\pi^0$ were fully reconstructed. Reaction cross sections were measured as a function of the photon energy from threshold up to $2.6\,$GeV with considerably improved statistics compared to a previous bubble chamber measurement. The cross sections rise monotonously with increasing photon energy. The two-particle mass distributions of $\Sigma^{\pm}\pi^{\mp}$ and $K^+\pi^-$ show substantial production of resonant states.