Related papers: Quarks and Anomalies
The pion structure function is investigated in a simple model, where the pion and its constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi -> gamma* pi scattering…
To describe pion as a bound state of two quark, when their current masses are non equal to zero, is considered. In the framefowrk of the potential approximate the Schwinger-Dyson and Bethe-Salpeter equations are solved. The quark-antiquark…
QCD is the fundamental theory to describe the strong interaction, where quarks and gluons have the color degrees of freedom. However, a single quark or gluon can not be separated out and all observable particles are color singlet states.…
It is shown that colour can only be defined on gauge invariant states. Since the ability to associate colour with constituent quarks is an integral part of the constituent quark model, this means that, if we want to extract constituent…
The thermodynamics of quantum chromodynamics at low temperatures and in sufficiently strong magnetic fields is governed by neutral pions. We analyze the interacting system of neutral pions and photons at zero baryon chemical potential using…
Effective three meson couplings, based in flavor U(3) quark-antiquark interactions, are considered to describe two light neutral axial meson Strong decays, $A \sim f_1(1285)$ and $f_{1S} (1420)$, and the charged rho meson decay in the…
A formal proof is given that the fermionic quasiparticle dispersion laws in a color superconductor are gauge independent. It is shown that the gluon (photon) field acquires a non-vanishing expectation value in a color superconductor, which…
We describe our recent proposal that distinct phases of gauge theories with fundamental quarks translate into specific types of low-energy behavior in Dirac spectral density. The resulting scenario is built around new evidence…
We suggest a new mechanism for the energy loss of fast heavy quarks in quark-gluon plasma. This mechanism is based on pion production caused by the anomalous chromomagnetic quark-gluon-pion interaction induced by strong topological…
We construct an effective Lagrangian which illustrates why color deconfines when chiral symmetry is restored in hot gauge theories with quarks in the fundamental representation. For quarks in the adjoint representation we show that while…
Recent results on pion physics from lattice QCD are reviewed. We discuss quark mass dependences of pion mass and decay constant and compare them with the predictions from chiral perturbation theory. In particular we focus on the convergence…
A kaon decaying into three pions is an example of a weak process. However, since the quarks are confined into mesons, the strong interaction also plays an important part. The reaction is a low-energy one, meaning that it takes place in the…
Chiral symmetry is restored at high density, quarks become nearly massless and pion, the Goldstone of the symmetry breaking decouples from the quarks. What happens at high density is important for finding the density dependence of Strange…
I discuss the interplay of infrared sensitivity in large order perturbative expansions with the presence of explicit nonperturbative corrections in the context of heavy quark expansions. The main focus is on inclusive decays and the status…
A collection of the physical observables, related to the electromagnetic properties of a nucleon, to investigate the non--perturbative quantum fluctuations in the strong interaction vacuum state under the influence of at least one close by…
This talk reports on work aimed at improving our understanding of charged states in gauge theories.Emphasis is placed on different ways of implementingthe gauge invariance of physical states. QED perturbative calculations are used to stress…
Quantum chromodynamics is the quantum gauge field theory that describes the strong interactions. This article reviews the basic structure, successes and challenges of quantum chromodynamics as it manifests itself at short and long…
The standard model of quarks and leptons is extended to connect three outstanding issues in particle physics and astrophysics: (1) the absence of strong CP nonconservation, (2) the existence of dark matter, and (3) the mechanism of nonzero…
I discuss some of the historical circumstances that drove us to use the lattice as a non-perturbative regulator. This approach has had immense success, convincingly demonstrating quark confinement and obtaining crucial properties of the…
The pions decouple from quarks while their coupling to nucleons $g_{\pi NN}$ remains unchanged at high density. This will have consequences for some recent papers.