Related papers: Light Scalar Mesons in Central Production at COMPA…
We describe a pion physics program attainable with the CERN COMPASS spectrometer, involving tracking detectors and an electromagnetic calorimeter. COMPASS can realize state-of-the-art pion beam hybrid meson and meson radiative transition…
The phenomena of strong running coupling and hadron mass generating have been studied in the framework of a QCD-inspired relativistic model of quark-gluon interaction with infrared confined propagators. We derived a meson mass equation and…
The COMPASS experiment at CERN SPS completed its data taking with hadron beams (p, \pi, K) in the years 2008 and 2009 by collecting a large set of data using different targets (H2, Pb, Ni, W). These data are dedicated to hadron…
A search for groups of collimated muons is performed using a data sample collected by the CMS experiment at the LHC, at a centre-of-mass energy of 7 TeV, and corresponding to an integrated luminosity of 35 inverse picobarns. The analysis…
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…
Diffractive dissociation reactions studied at the COMPASS experiment at CERN provide access to the light-meson spectrum. During a pilot run in 2004, using a pion beam and a lead target, 420k \pi- \pi- \pi+ final-state events with masses…
COMPASS is a running fixed-target experiment at the CERN SPS with a rich physics program focused on nucleon spin structure and on hadron spectroscopy. One of the main goals of the spin program is the measurement of the transverse spin…
Experiments that study the photoproduction of pseudoscalar mesons; pions, etas and kaons, have the potential to increase our knowledge of baryon and hyperon resonance properties. Recent experiments at JLab, Mainz, GRAAL, and Bonn are…
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…
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,…
Since Quantum Choromdynamics allows for gluon self-coupling, quarks and gluons cannot be observed as free particles, but only their bound states, the hadrons. This so-called confinement phenomenon is responsible for $98\%$ of the mass in…
The COMPASS experiment at CERN has collected a large data sample of 50 million diffractively produced $\pi^-\pi^+\pi^-$ events using a $190\,$GeV$/c$ negatively charged hadron beam. The partial-wave analysis (PWA) of these high-precision…
While the spectrum of non-strange light mesons is well known, many predicted strange mesons have not yet been observed, and many potentially observed states require further confirmation. Using the $K^-$ component of the hadron beam at the…
One of the key objectives of the COMPASS experiment at CERN is the determination of the gluon contribution to the nucleon spin. The gluon polarization is measured via photon-gluon fusion in deep-inelastic scattering of 160 GeV/c polarized…
The existence of non-q\bar{q} hadrons such as glueballs and hybrids is one of the most important qualitative questions in QCD. The COMPASS experiment offers the possibility to unambiguously identify such states and map out the glueball and…
At the COMPASS experiment, diffractive dissociation of the beam proton is one of the dominant processes for the 190GeV/c positive hadron beam impinging on a liquid hydrogen target. The status of the analysis of the reactions pp -> p_f pi^+…
In 2016 and 2017, the COMPASS Collaboration at CERN collected a large sample of DIS events with a longitudinally polarized 160 GeV/c muon beam scattering off a liquid hydrogen target. Part of the collected data has been analyzed to extract…
The recently proposed COMPASS experiment at CERN attempts a measurement of the gluon polarisation with a precision of delta(Delta g/g) = 0.1. The experiment uses open charm muoproduction to tag the photon-gluon fusion process.
We study the excitation spectrum of light and strange mesons in diffractive scattering. We identify different hadron resonances through partial wave analysis, which inherently relies on analysis models. Besides statistical uncertainties,…
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…