1,382 research outputs found
COMPASS Calorimetry in view of future plans
The COMPASS experiment at the CERN SPS is dedicated to hadron physics with a
broad research programme, including the study of the nucleon spin structure
using muons as a probe and a variety of issues in meson spectroscopy using
hadron beams. The two stage fixed target spectrometer with electromagnetic (em)
and hadronic calorimetry in both stages provides photon detection in a wide
angular range. As discussed in this paper, the COMPASS em calorimetry plays a
crucial r\^{o}le for the Hadron programme started in 2008 as well as for the
planned COMPASS future programme of measuring GPDs via exclusive DVCS photons.
We present the photon detection coverage foreseen, and first, preliminary
results characterising the present performances of both existing COMPASS
electromagnetic calorimeters, based on test beam data taken at CERN T9 facility
end of 2007
COMPASS Hadron Spectroscopy -- Final states involving neutrals and kaons
The COMPASS experiment at CERN is well designed for light-hadron spectroscopy
with emphasis on the detection of new states, in particular the search for
-exotic states and glueballs. We have collected data with 190 GeV/c
charged hadron beams on a liquid hydrogen and nuclear targets in 2008/09. The
spectrometer features good coverage by electromagnetic calorimetry and a RICH
detector further provides / separation, allowing for studying final
states involving neutral particles like or as well as hidden
strangeness, respectively. We discuss the status of ongoing analyses with
specific focus on diffractively produced as well as
final states.Comment: 3 pages, 4 figures, Conf. Proc., to appear in the Intern. Journal of
Modern Phys. A, 11th Intern. Workshop on Meson Production, Properties and
Interaction, KRAK\'OW, POLAND, 10-15 June 201
On the disputed resonance and observation of a new iso-vector resonance
The COMPASS experiment at CERN delivers new results on the search for exotic
mesons. A spin-exotic resonance, the , was reported by several
experiments in the past. Those observations are, however, still to date highly
disputed in the community. Especially the decay channel allows for
simultaneous observation of well established and less known resonances in
different decay modes. The results from amplitude analysis of diffractively
produced final states show consistently a spin-exotic signal, that
appears in agreement with previous observations of the . The
high-statistics 2008 data sample allows and demands for an extended amplitude
analysis method that further disentangles resonant and non-resonant particle
production. The present status of analysis of COMPASS data and the observation
of a new iso-vector meson is discussed.Comment: 6 pages, 24 figures, DSPIN-13 Conference Proceedings, to appear in
the proceedings of the XV Workshop on High Energy Spin Physics, Dubna,
Russia, October 8-12, 201
Meson spectroscopy with COMPASS
The COMPASS fixed-target experiment at CERN SPS is dedicated to the study of
hadron structure and dynamics. In the physics programme using hadron beams, the
focus is on the detection of new states, in particular the search for
exotic states and glueballs. After a short pilot run in 2004 (190 GeV/c
negative pion beam, lead target), we started our hadron spectroscopy programme
in 2008 by collecting an unprecedented statistics with a negative hadron beam
(190 GeV/c) on a liquid hydrogen target. A similar amount of data with positive
hadron beam (190 GeV/c) has been taken in 2009, as well as some additional data
with negative beam on nuclear targets. The spectrometer features a large
angular acceptance and high momentum resolution and also good coverage by
electromagnetic calorimetry, crucial for the detection of final states
involving or . A first important result is the observation of a
significant spin exotic signal consistent with the disputed
in the pilot run data. This result was recently published. We
present an overview of the status of various ongoing analyses on the 2008/09
data.Comment: 6 pages, 6 figures, to appear in the proceedings of the International
Nuclear Physics Conference 2010, Vancouver, Canada, 04-09 Jul 201
A Macroscopic Description of Coherent Geo-Magnetic Radiation from Cosmic Ray Air Showers
We have developed a macroscopic description of coherent electro-magnetic
radiation from air showers initiated by ultra-high energy cosmic rays due to
the presence of the geo-magnetic field. This description offers a simple and
direct insight in the relation between the properties of the air shower and the
time-structure of the radio pulse.Comment: 10 pages, 8 figures; submitted to Astroparticle Physic
Hadron Spectroscopy with COMPASS at CERN
The aim of the COMPASS hadron programme is to study the light-quark hadron
spectrum, and in particular, to search for evidence of hybrids and glueballs.
COMPASS is a fixed-target experiment at the CERN SPS and features a two-stage
spectrometer with high momentum resolution, large acceptance, particle
identification and calorimetry. A short pilot run in 2004 resulted in the
observation of a spin-exotic state with consistent with the
debated . In addition, Coulomb production at low momentum transfer
data provide a test of Chiral Perturbation Theory. During 2008 and 2009, a
world leading data set was collected with hadron beam which is currently being
analysed. The large statistics allows for a thorough decomposition of the data
into partial waves. The COMPASS hadron data span over a broad range of channels
and shed light on several different aspects of QCD.Comment: 4 pages, 5 figure
- …