Related papers: Highlights from COMPASS in hadron spectroscopy
The vast bulk of visible mass emerges from nonperturbative dynamics within quantum chromodynamics (QCD) -- the strong interaction sector of the Standard Model. The past decade has revealed the three pillars that support this emergent hadron…
Despite that quantum chromodynamics, the theory of strong interaction, has colorful quarks and gluons as its basic degrees of freedom, all fundamental particles participating the strong interaction that can be directly detected in…
A basic understanding of the relevant features of hadron properties from first principles QCD has remained elusive, and should be understood as emergent phenomena which depend critically on the number of dimensions of physical spacetime.…
Just as Quantum Electrodynamics describes how electrons are bound in atoms by the electromagnetic force, mediated by exchange of photons, Quantum Chromodynamics (QCD) describes how quarks are bound inside hadrons by the strong force,…
QCD theory allows the existence of states which cannot be built by the naive quark model; both theoretical arguments and experimental data confirm the hypothesis that gluons may have freedom degrees at the constituent level, and should be…
A phenomenological model for the quark structure of mesons is considered. The model is based on the tube model for QCD, where all quanta with nonzero transverse momenta are neglected. In the limit that the mass term of the gluons goes to…
The proton mass arises from spontaneous breaking of chiral symmetry and the formation of constituent quarks. Their dynamics cannot be tested by proton tomography but only by studying excited baryons. However, the number of excited baryons…
The model of induced quark currents formulated in our recent paper (Phys. Rev. D51, 176) is developed. The model being a kind of nonlocal extension of the bosonization procedure is based on the hypothesis that the QCD vacuum is realized by…
A distinct feature of Coulomb gauge QCD is that it can be formulated in terms of physical, transverse gluons and quarks alone. The state-counting is then transparent, and the gauge is suited for studies of the excited spectrum. Leaving…
We survey the current status of light meson spectroscopy. We begin with a general introduction to meson spectroscopy and and its importance in understanding the physical states of Quantum Chromo Dynamics (QCD). Phemenological models of…
The COMPASS experiment makes use of the CERN SPS high-intensitymuon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the…
COMPASS is a fixed-target experiment at CERN SPS which focused on light-quark hadron spectroscopy during the data taking in 2008 and 2009. A world-leading data set was collected with a 190GeV/c hadron beam impinging on a liquid hydrogen…
The real-world properties of quantum chromodynamics (QCD) - the strongly-interacting piece of the Standard Model - are dominated by two emergent phenomena: confinement; namely, the theory's elementary degrees-of-freedom - quarks and gluons…
The strong interaction is the fundamental force that holds quarks and the gluon force carriers together to form protons and neutrons and also binds the atomic nucleus. The theory governing quark-gluon interactions is Quantum Chromodynamics…
This work presents a new phenomenological description of QCD vacuum where the color background field is depicted by a constant parallel vector with amplitude proportional to $\sigma\sim 0.28 GeV^2$. The familiar Regge relation can be…
The COMPASS experiment at CERN is dedicated to light hadron spectroscopy with emphasis on the detection of new states, in particular the search for spin exotic states and glueballs. After a short pilot run in 2004 (190 GeV/c $\pi^{-}$ beam,…
An overarching scientific challenge for the coming decade is to discover the meaning of confinement, its relationship to dynamical chiral symmetry breaking (DCSB) - the origin of visible mass - and the connection between them. In…
A simple model of hadron which exhibits the quark confinement and the asymptotic freedom is described. The hadron is modelled as a sphere of radius equal to its Compton wavelength in which quarks occur surrounded by space with the uniformly…
Based on a Lagrangian with a coupling of two gluons to J^pi=0^+ (the quantum numbers of the vacuum) which decay to q-qbar pairs, a model is presented, in which hadrons couple directly to the absolute vacuum of fluctuating gluon fields. By…
COMPASS is a multi-purpose fixed-target experiment at CERN aimed at studying the structure and spectrum of hadrons. It has collected the so far world's largest data set on diffractive production of the $K^-\pi^-\pi^+$ decay, which in…