Proton-Antiproton Annihilation and Meson Spectroscopy with the Crystal Barrel

TL;DR

The Crystal Barrel experiment at CERN studied proton-antiproton annihilation, identifying scalar mesons and providing insights into annihilation mechanisms and potential glueball states through extensive data collection and analysis.

Contribution

This work presents new measurements of annihilation channels and identifies scalar mesons, including a potential scalar glueball, advancing understanding of hadron structure.

Findings

Identified three scalar mesons: a0(1450), f0(1370), f0(1500)

Measured annihilation rates into various channels

Suggested f0(1500) as a possible scalar glueball

Abstract

This report reviews the achievements of the Crystal Barrel experiment at the Low Energy Antiproton Ring (LEAR) at CERN. During seven years of operation Crystal Barrel has collected very large statistical samples in pbarp annihilation, especially at rest and with emphasis on final states with high neutral multiplicity. The measured rates for annihilation into various two-body channels and for electromagnetic processes have been used to test simple models for the annihilation mechanism based on the quark internal structure of hadrons. From three-body annihilations three scalar mesons, a0(1450), f0(1370) and f0(1500) have been established in various decay modes. One of them, f0(1500), may be identified with the expected ground state scalar glueball.