Related papers: Baryon Spectroscopy at COMPASS
We present results of meson and baryon spectroscopy using the Chirally Improved Dirac operator on lattices of size 16**3 x 32 with two mass-degenerate light sea quarks. Three ensembles with pion masses of 322(5), 470(4) and 525(7) MeV and…
On the basis of the experimental data on diffractive processes in $\pi p$, $pp$ and $p \bar p$ collisions at intermediate, moderately high and high energies, we restore the scattering amplitude related to the $t$-channel exchange by vacuum…
Despite decades of research, we still lack a detailed quantitative understanding of the way quantum chromodynamics (QCD) generates the spectrum of hadrons. Precise experimental studies of the hadron excitation spectrum and the dynamics of…
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…
Hadron spectroscopy is an important tool towards the study of internal quark dynamics in a composite system. The present article focuses on the study of resonance spectra of strange baryons with S=-2, -3. The non-relativistic approach…
Two charged pion final states are studied for GeV photons incident on protons. The data come from Thomas Jefferson National Accelerator Facility using the CLAS detector. A tagged photon beam of 0.5-2.4 GeV/c was produced through…
COMPASS is a multi-purpose fixed-target experiment at the CERN SPS. One of its main goals is to probe the strong interaction at low energies by studying the excitation spectrum of light mesons in diffractive scattering reactions of a $190\…
An overview on the new COMPASS II experimental programme is presented. The main topics include a study of Primakoff reactions, generalised parton distributions via deeply virtual Compton scattering and transverse momentum dependent…
In diffractive interactions of protons or nuclei a violent collision can occur that leaves the forward going particle completely intact -with probability determined by the structure of the proton or nucleus. At very high energies these…
We calculate the differential cross section and single-polarization observables for the reaction $\gamma p \to \Phi p$ within perturbative QCD, treating the proton as a quark-diquark system. The phenomenological couplings of gauge bosons to…
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 key reactions to study the Generalised Parton Distributions are Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP). At COMPASS, these processes are investigated using a high intensity muon beam with a…
The baryon number transfer is studied in elementary and complex hadronic interactions at the CERN experiment NA49 at the SPS, at 158 AGeV beam energy (\sqrt{s}=17.2 GeV). A two component picture is proposed, which builds up the net proton…
The diffractive scattering of photon off proton $\gamma^{(*)} p \to \gamma Y$ (where $Y$ denotes the proton dissociative system or the elastically scattered proton) is measured in two different kinematic regimes at high energy with the H1…
The COMPASS fixed-target experiment at the CERN SPS is dedicated to the study of hadron structure and dynamics. One goal of the physics programme using hadron beams is the search for new states, in particular the search for $J^{PC}$ exotic…
The $\Xi_c^+ \pi^- \pi^+$ spectrum is investigated using proton-proton collisions at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 5.4fb$^{-1}$, collected by the LHCb experiment during 2016--2018. Four…
Soft diffractive cross sections in $pp$ (or $\bar pp$), $\pi p$ and $\gamma p$ collisions are calculated using QCD-motivated pomeron. The $s$-channel unitarization of the amplitude is performed by the eikonal approach, and in the framework…
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…
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 $e^+e^-$ collision samples corresponding to an integrated luminosity of 4.4 $\mbox{fb$^{-1}$}$ collected with the BESIII detector at center-of-mass energies between $4.6\,\,\mathrm{GeV}$ and $4.7\,\,\mathrm{GeV}$, a partial wave…