COmmon Muon Proton Apparatus for Structure and Spectroscopy

Issue 2015/55-05
Issue 2015/55-02
Issue 2010/09
Issue 46-6
Issue 46-4
Issue 39-7

2006/06 | scan

IWHSS 2017 Cortona
Physics Beyond Colliders, March meeting
Workshop: Beyond 2020
Goldstone nature of the pion confirmed (Press)
Science Ticker: a1(1420) (pdf)
Welt der Physik
SPS experiment NA58 safety


COMPASS is a high-energy physics experiment at the Super Proton Synchrotron (SPS) at CERN  in Geneva, Switzerland. The purpose of this experiment is the study of hadron structure and hadron spectroscopy with high intensity muon and hadron beams. 

On February 1997 the experiment was approved conditionally by  CERN and the final Memorandum of Understanding was signed in September 1998. The spectrometer was installed in 1999 - 2000 and was commissioned during a technical run in 2001. Data taking started in summer 2002 and continued until fall 2004. After one year shutdown in 2005, COMPASS resumed data taking with a muon beam in 2006 and 2007. The years 2008 and 2009 were dedicated to the COMPASS hadron spectroscopy programme with pion and proton beam. In 2010 and 2011 spin structure function measurements with a polarised proton target were performed.

In 2010 an extension of the COMPASS program has been approved by the CERN Research Board. It consists in a set of measurements to study the structure of hadrons in Deep Virtual Compton Scattering (DVCS), Hard Exclusive Meson Production (HEMP), SIDIS, Polarized Drell-Yan and Primakoff reactions. Further investigations in the field of hadron spectroscopy were envisaged as well. On January 2013 a new Memorandum of Understanding was signed, in order to fulfill this program. In 2012 the data to study the Primakoff reaction were taken. The first (pilot) run for the DVCS measurement was also achieved. The first-ever polarised Drell-Yan measurement with a beam of negative pions and a polarised proton target was succesfully performed in 2015. Now the experiment has been modified for the 2016/2017 GPD runs with a liquid hydrogen target and a muon beam.

Nearly 220 physicists from 13 countries and 24 institutions work in COMPASS.



Who is who and Responsibilities

GPD run 2017 (2016)

Drell-Yan run 2014, 2015


Muon   run 2011, 2010

Members (COMPASS I)

Hadron run 2012, 2009, 2008, old
  Collaboration Board       Muon   run 2007, 2006, 2004
  Technical Board       An online event display

Home Pages

The M2 beam line
  Summer Students       Electronic logbook
  Compass Phonebook       DAQ
  Mailing & Discussions       COMPASS Wiki
  Election 2013 2015       CDR status
  Visits       DCS
      Beam Monitoring
        New logbook (test)

Artistic view of the 60 m long COMPASS two-stage spectrometer. The two dipole magnets are indicated in red.



  Compass Set-up       Analysis Meetings
  Hadron Calorimeters       Software
  EM Calorimeters       Seminars
  GEM detectors       ELOG logbooks
  Trigger       PUBLICATIONS
  RICH       Publications-all page

RICH Upgrade

  W45       Target Papers
  SM1 Magnet       Theses
  Polarized Target       Talks
  Cedars       Conference Papers
  Compass Gallery       Compass Notes
          Released results
  Transversity       Collaboration Meetings
      Weekly meetings
  Drell-Yan       TB meetings
  Hadron analysis       FE meetings
        Meetings database
  My Mail and More       CERN Map/Buildings
  CERN       Experiments at CERN
  High Energy Physics       CERN Stores
  WWW       Document Server


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