Spin Physics at Compass

TL;DR

COMPASS at CERN investigates hadron structure and spectroscopy using muon and hadron beams, aiming to understand nucleon spin contributions and search for exotic states like glueballs through polarized scattering experiments.

Contribution

This paper reports preliminary results from the 2002 data run, demonstrating the experiment's capability to explore hadron asymmetries and exotic states.

Findings

Initial measurements of hadron asymmetries in muon-nucleon scattering.

Evidence supporting the experiment's potential to determine gluon contributions to nucleon spin.

First observations of candidate exotic states in the collected data.

Abstract

COMPASS is a new fixed target experiment presently in operation at CERN. It has the goal to investigate hadron structure and hadron spectroscopy by using either muon or hadron beams. From measurements of various hadron asymmetries in polarized muon - nucleon scattering it will be possible to determine the contribution of the gluons to the nucleon spin. Main objective of the hadron program is the search of exotic states, and glueballs in particular. This physics programme is carried out with a two-stage magnetic spectrometer, with particle identification and calorimetry in both stages, which has started collecting physics data in 2002, and will run at the CERN SPS at least until 2010. Preliminary results from the 2002 run with a 160 GeV muon beam are presented for several physics channels under investigation.