A New QCD Facility for the CERN SPS

CERN provides a variety of high-energy beams for nuclear and particle
physics research. Among those delivered to the North Area, is the beam line M2
which is optimized to deliver an intense muon beam, but also hadron beams
of both polarities. They are brought to an overground hall, which has been
used in the past years almost exclusively by the COMPASS collaboration,
with a broad experimental physics program on Quantum Chromodynamics (QCD).

Since many questions around QCD remain still open, a new collaboration
is currently forming, in the quest for setting up a new QCD facility in that
place, and aims at a modern detector architecture and
a large variety of measurements. Those range from lowest-Q^2
physics as the determination of the proton radius from elastic
muon-proton scattering, to average-Q^2 reactions for hadron spectroscopy
and high-Q^2 hadron structure investigations via the Drell-Yan process and
deeply-virtual Compton scattering.

We will give an overview over the status of the project and its Letter of
Intent. Focus will be given to the elastic muon-proton scattering measurement,
which involves planned contributions from GSI and PNPI (St. Petersburg), and
some aspects of the hadron structure and spectroscopy program with antiproton
and kaon beams. The M2 beam line is intended to be upgraded in order to provide
radio-frequency separation of the hadron components, carrying forward a unique
QCD facility for many years to come.