Improved study of a possible Theta+ production in the pp -> p K0 sigma+ reaction with the COSY-TOF spectrometer

TL;DR

This study used the COSY-TOF spectrometer to investigate the pp -> p K0 Sigma+ reaction at 3.059 GeV/c, aiming to detect the Theta+ pentaquark, but found no evidence for its existence, setting an upper cross section limit.

Contribution

The paper provides the first high-statistics search for the Theta+ pentaquark in this reaction, setting new upper limits on its production cross section.

Findings

No evidence of Theta+ pentaquark was observed.

Upper limit for the cross section is < 0.15 microbarn at 95% confidence.

Results do not support the existence of Theta+ in this channel.

Abstract

The pp -> p K0 Sigma+ reaction was investigated with the TOF spectrometer at COSY at 3.059 GeV/c incident beam momentum. The main objective was to clarify whether or not a narrow exotic S = +1 resnance, the Theta+ pentaquark, is populated at 1.53 GeV/c2 in the K0 p subsystem with a data sample of much higher statistical significance compared to the previously reported data in this channel. An analysis of these data does not confirm the existence of the Theta+ pentaquark. This is expressed as an upper limit for the cross section sigma (pp -> p K0 Sigma+) < 0.15 microbarn at the 95 percent confidence level.