Related papers: Symmetries in subatomic multi-quark systems
We discuss the separation of isospin-symmetric and isospin-breaking contributions in the hadronic observables within the framework of QCD plus QED. Further, we briefly review some recent work on the low-energy hadron phenomenology, in which…
The covariant parton model (CPM) is a consequent application of the parton model concept to the nucleon structure. In this model, there is a choice to put quarks either in a pure-spin state or in a mixed-spin state. We show that the…
We study the color correlation between two static quarks in 3Q ($QQQ$) and 4Q ($QQ\bar Q\bar Q$) multiquark systems at $T=0$ based on the reduced two-body density matrices $\rho$ in color space. We perform quenched lattice QCD calculations…
The isospin asymmetry of the sea quark distribution as well as the unexpectedly small quark spin fraction of the nucleon are two outstanding discoveries recently made in the physics of deep-inelastic structure functions. We evaluate here…
Basic problems of the semiclassical microscopic modelling of strongly interactingsystems are discussed within the framework of Quantum Molecular Dynamics (QMD). This model allows to study the influence of several types of nucleonic…
Several topics in hadron physics at different scales of resolution are discussed. First, deep-inelastic scattering from nucleons and nuclei is viewed in a light-cone coordinate space picture. Then the smooth transition from parton to hadron…
We show that requiring the quark partition function to be color singlet of SU(3) color gauge group leads to reordering the thermodynamic potential in terms of the colorless multi-quark modes ($q{\bar q}, qqq, {\bar q}{\bar q}{\bar q}, ...$)…
The Global Colour Model(GCM) of QCD is used to extract low energy quark-gluon processes from experimental data. The resultant effective quark-quark coupling correlator is compared with that of Jain and Munczek, and with the combined lattice…
We compute the spectrum of the low-lying mesonic states with vector, scalar and pseudoscalar quantum numbers in QCD with one flavour. With three colours the fundamental and the two-index anti-symmetric representations of the gauge group…
In Quantum Chromodynamics (QCD) the eigenmodes of the Dirac operator with small absolute eigenvalues have a close relationship to the dynamical breaking of the chiral symmetry. In a simulation with two dynamical quarks, we study the…
The order parameter of the chiral phase transition is directly related to the infrared part of the spectrum of the QCD Dirac operator. This part of the spectrum follows from the low energy limit of QCD which is given by a partition function…
Quantum Chromodynamics (QCD) is the fundamental theory describing quark interactions, and various quark models based on QCD have been widely used to study the properties of hadrons, including their structures and mass spectra. However,…
I present an introduction to the field of Quantum Chromodynamics (QCD) with emphasis on nucleon spin structure and perturbative methods. After a somewhat comprehensive overview of perturbative QCD, including the systematics of…
A survey is given on selected topics concerning the role of spontaneous chiral symmetry breaking in low-energy QCD, and its dynamical implications for nuclear systems. This includes aspects of chiral thermodynamics (the temperature and…
A generalized linear sigma model is employed to study the quark structure of low lying scalar as well as pseudoscalar states. The model allows the possible mixing of quark anti-quark states with others made of two quarks and two antiquarks…
A six-quark state with the benzene-like structure is proposed and studied based on color string model. The calculation with the quadratic confinement show that such structure has the lowest energy among the various hidden color six-quark…
It is commonly believed that ${\pi}^0 \to 2 \gamma$ decay shows that there are three colours in Quantum Chromodynamics (QCD). It is shown here that this is not correct. When correct colour dependent charges of the quarks are considered then…
Simple quark models for the low lying vector mesons suggest a mixing between the u- and d-flavors and a violation of the isospin symmetry for the $\rho-\omega$- system much stronger than observed. It is shown that the chiral dynamics,…
The theory of strong interactions, quantum chromodynamics (QCD), is quite successful in the prediction and description of main features of multiparticle production processes at high energies. The general perturbative QCD approach to these…
We present virtual contributions up to two loop level in perturbative Quantum Chromodynamic (QCD) to the decay of pseudo-scalar Higgs boson ($A$) to three gluons ($g$) and also to quark ($q$), anti-quark ($\overline q$) and a gluon. With…