Study of Inclusive Strange-Baryon Production and Search for Pentaquarks in Two-Photon Collisions at LEP

TL;DR

This paper measures the production rates of certain strange baryons in two-photon collisions at LEP and searches for the pentaquark theta+(1540), finding no evidence for its existence but generally aligning with theoretical models.

Contribution

It provides the first detailed measurements of Lambda, Xi-, and Xi*(1530) production in two-photon collisions and conducts a search for the pentaquark theta+(1540).

Findings

Measured differential cross sections for Lambda and Xi- baryons.

Found no evidence for pentaquark theta+(1540) production.

Observed agreement with theoretical models and Monte Carlo predictions.

Abstract

Measurements of inclusive production of the Lambda, Xi- and Xi*(1530) baryons in two-photon collisions with the L3 detector at LEP are presented. The inclusive differential cross sections for Lambda and Xi- are measured as a function of the baryon transverse momentum, pt, and pseudo-rapidity, eta. The mean number of Lambda, Xi- and Xi*(1530) baryons per hadronic two-photon event is determined in the kinematic range 0.4 GeV < pt< 2.5 GeV, |eta| < 1.2. Overall agreement with the theoretical models and Monte Carlo predictions is observed. A search for inclusive production of the pentaquark theta+(1540) in two-photon collisions through the decay theta+ -> proton K0s is also presented. No evidence for production of this state is found.