Related papers: Hadron Spectroscopy with COMPASS
Fragmentation functions represent a key ingredient to address the proton spin structure in semi-inclusive deep-inelastic scattering and proton-proton collisions. They can not be determined from perturbative Quantum Chromodynamics and have…
The study of transverse spin effects is part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. COMPASS investigates the transversity PDFs in semi-inclusive DIS, using a longitudinally polarized muon beam of…
The main goal of the spectroscopy program at COMPASS is to explore the light-meson spectrum below about $2\,\text{GeV}/c^2$ in diffractive production. Our flagship channel is the decay into three charged pions: $p + \pi^-\to \pi^-\pi^-\pi^+…
The HERMES and SMC experiments have determined the contribution of different quark flavors to the nucleon spin in a large range of Bjorken-x via semi-inclusive deep inelastic scattering. The main goal of the COMPASS experiment is to measure…
One of the important goals of the COMPASS experiment is the determination of the gluonic contribution to the spin of the nucleon. By using the photon gluon fusion (PGF) process in polarised deep inelastic scattering direct access to the…
The COMPASS spectrometer at CERN has collected a large data set for diffractive three-pion production of $46\times10^6$ exclusive events. Based on previous conventional Partial-Wave Analyses (PWA), we performed a `freed-isobar PWA' on the…
COMPASS is a fixed target experiment at CERN. Part of its physics programme is dedicated to study the transverse spin and the transverse momentum structure of the nucleon using SIDIS. For these measurements, data have been collected using…
COMPASS is a fixed-target experiment on the SPS M2 beamline at CERN. Its LiD target can be polarised both longitudinally and transversally with respect to the longitudinally polarised 160 GeV/c muon beam. Approximately 20% of the beam-time…
Modern hadron-spectroscopy experiments such as COMPASS collect data samples of unprecedented size, so that novel analysis techniques become possible and necessary. One such technique is the freed-isobar partial-wave analysis (PWA). In this…
CERN COMPASS can investigate pion-photon interactions, to achieve a unique Primakoff Coulomb physics program, centered on pion polarizability and hybrid meson structure studies. COMPASS uses 100-280 GeV beams (muon, pion) and a virtual…
The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the pi- pi- pi+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of…
Based on the largest event sample of diffractively produced $\pi^-\pi^-\pi^+$, obtained by a pion beam of $190~\rm{GeV/c}$ momentum, the COMPASS collaboration has performed the most advanced partial wave analysis on multi-body final states,…
We describe a hadron physics program attainable with a partially instrumented CERN COMPASS spectrometer, involving tracking detectors and moderate-size ECAL2/HCAL2 calorimeters. COMPASS can realize a state-of-the-art hadron beam physics…
One of the goals of the COMPASS experiment is the precision study of light-meson spectroscopy with data for various final states. With $46\times10^6$ exclusive events, the process $\pi^- p\to\pi^-\pi^+\pi^- p$ constitutes the flagship…
One of the main aims of the COMPASS experiment at CERN is the study of the spin structure of the nucleon and in particular the determination of the gluon polarization in the nucleon. We present some new results of 2002-2003 data analysis.…
COMPASS is a fixed target experiment presently running at CERN. In 2002, 2003, and 2004 the experiment used a 160 GeV polarized muon beam coming from SPS and scattered off a $^6$LiD target. The nucleons in the target can be polarized either…
COMPASS at CERN is preparing for a new series of measurements on the nucleon structure comprising deep virtual Compton scattering and hard exclusive meson production using muon beams, as well as Drell-Yan reactions using a polarised proton…
We discuss the status of analyses of data recorded in the 2008 and 2009 runs of the COMPASS experiment at CERN with sepcific focus on final states with $K^0_S K^0_S \pi^-$ and $K^+K^-\pi^-$ produced in $\pi^-(190\,\textrm{GeV})p$…
One of the goals of the COMPASS experiment is the determination of the gluon polarisation \Delta G/G, for a deep understanding of the spin structure of the nucleon. In DIS the gluon polarisation can be measured via the Photon-Gluon-Fusion…
We report on the results of a novel partial-wave analysis based on $50\cdot 10^6$ events from the reaction $\pi^- + p \to \pi^-\pi-^\pi^+ + p_\text{recoil}$ at 190 $\text{GeV/c}$ incoming beam momentum using the COMPASS spectrometer. A…