Hyperon production asymmetries in 500 GeV/c pion nucleus interactions

TL;DR

This paper reports on the measurement of production asymmetries of hyperons and anti-hyperons in 500 GeV/c pion-nucleus interactions, revealing differences in asymmetry patterns related to quark content and fragmentation regions.

Contribution

It provides the first detailed study of hyperon production asymmetries as a function of x_F and p_t^2 in high-energy pion-nucleus collisions, highlighting diquark effects and valence quark influences.

Findings

Asymmetry in target fragmentation region larger for Lambda^0 than Xi.

Omega asymmetry significantly smaller, indicating no shared valence quarks.

Asymmetries tend to 0.1 in beam fragmentation region and are constant with p_t^2.

Abstract

We present a preliminary study from Fermilab experiment E791 of Lambda^0 / Lambda^0 bar, Xi^- / Xi^+ and Omega^- /Omega^+ production asymmetries from pi^- nucleus interactions at 500 Gev/c. The production asymmetries for these particles are studied as a function of x_F and pt^2. We observed an asymmetry in the target fragmentation region for Lambda^0's larger than that for Xi's, suggesting diquark effects. The asymmetry for Omega's is significatively smaller than for the other two hyperons consistent with the fact that Omega's do not share valence quarks with either the pion or the target particle. In the beam fragmentation region, the asymmetry tends to 0.1 for both Lambda^0's and Xi's. The asymmetries vs pt^2 are approximately constant for the three strange baryons under study.