The COMPASS Hadron Spectroscopy Programme

TL;DR

The COMPASS experiment at CERN investigates hadron structure and dynamics, focusing on light-quark spectroscopy, exotic mesons, and baryons using high-statistics data and advanced analysis techniques to explore fundamental QCD phenomena.

Contribution

This paper presents new high-statistics data and analysis methods for light-quark hadron spectroscopy, including spin-exotic mesons and baryons, advancing understanding of QCD resonances.

Findings

Observation of a spin-exotic resonance

Identification of glueball candidates

Detailed partial wave analysis results

Abstract

COMPASS is a fixed-target experiment at the CERN SPS for the investigation of the structure and the dynamics of hadrons. The experimental setup features a large acceptance and high momentum resolution spectrometer including particle identification and calorimetry and is therefore ideal to access a broad range of different final states. Following the promising observation of a spin-exotic resonance during an earlier pilot run, COMPASS focused on light-quark hadron spectroscopy during the years 2008 and 2009. A data set, world leading in terms of statistics and resolution, has been collected with a 190GeV/c hadron beam impinging on either liquid hydrogen or nuclear targets. Spin-exotic meson and glueball candidates formed in both diffractive dissociation and central production are presently studied. Since the beam composition includes protons, the excited baryon spectrum is also accessible. Furthermore, Primakoff reactions have the potential to determine radiative widths of the resonances and to probe chiral perturbation theory. An overview of the ongoing analyses will be presented. In particular, the employed partial wave analysis techniques will be illustrated and recent results will be shown for a selection of final states.