Related papers: A Conjecture about Hadrons
We briefly review the status of our understanding of hadron structure based on QCD. This includes the role of symmetries, especially chiral symmetry, and the insights provided by lattice QCD. The main focus is on baryon structure and…
Chiral quark models offer a practical and simple tool to describe covariantly both low and high energy phenomenology in combination with QCD evolution. This can be done in full harmony with chiral symmetry and electromagnetic gauge…
Diagrammatic methods and Large $N_c$ QCD are used to argue that the nucleon as calculated in quenched QCD contains physics which can be ascribed to the pion cloud of the nucleon. In particular, it is argued that the physics corresponding to…
Quark model with potentials derived from QCD, including the quark-diquark model for excited hadrons gives mass formulae in very good agreement with experiment and goes a long way in explaining the approximate symmetries and supersymmetries…
The folklore tradition about the QCD phase diagram is that at the chiral restoration phase transition at finite density hadrons are deconfined and there appears the quark matter. We address this question within the only known exactly…
We discuss progress in understanding the light and heavy quark excited hadron spectrum from Coulomb gauge QCD. For light quark systems we highlight the insensitivity to spontaneous chiral symmetry breaking, which predicts Wigner…
It has long been expected that the spectrum of hadrons in QCD would be far richer and extensive than experiment has so far revealed. While there have been experimental hints of this richness for some time, it is really only in the last few…
We present that including the hadron loop effects could help us to understand the spectrum of the heavier charmonium-like states and their decays simultaneously. The observed states could be represented by the poles on the complex energy…
Two ideas have greatly contributed to our understanding of baryon structure in the framework of Quantum Chromodynamics (QCD). The first, chiral symmetry, received its fundamental justification from QCD and has been developed into the…
We calculate the spectral density of the Dirac operator over an ensemble of configurations composed of overlapping instantons and anti-instantons. We find evidence that the spectral density diverges in the limit of small eigenvalues. This…
Broken chiral symmetry has become the basis for a unified treatment of hadronic interactions at low energies. After reviewing mechanisms for spontaneous chiral symmetry breaking, I outline the construction of the low--energy effective field…
Light-front holographic QCD provides a successful first approximation to hadron spectroscopy in the chiral limit of $(3+1)$-dim light-front QCD, where a holographic Schr\"odinger-like equation, with an emerging confining scale, $\kappa$,…
A new "Hidden Colour Hypothesis" within the framework of QCD, as an extension of and in keeping with the spirit of the "Colour Singlet Hypothesis" is hereby proposed As such it should play a role in a consistent description of exotic…
I explain the concept that light quarks diffuse in the QCD vacuum following the spontaneous breakdown of chiral symmetry. I exploit the striking analogy to disordered electrons in metals, identifying, among others, the universal regime…
We have recently completed the one loop calculation of meson-meson scattering within Chiral Perturbation Theory. Once unitarized, these amplitudes provide simultaneously a remarkable description of the resonance region up to 1.2 GeV as well…
Analytic properties of hadronic amplitudes are discussed within the framework of QCD as formulated on the basis of the BRST algebra. Local, composite fields are introduced for hadrons. Given confinement, it is shown that hadronic amplitudes…
Electromagnetic properties of hadrons can be computed by lattice simulations of QCD in background fields. We demonstrate new techniques for the investigation of charged hadron properties in electric fields. Our current calculations employ…
The spectrum of the C=1 hyperons is well described by the constituent quark model, if the fine structure interaction between the light and strange quarks is mediated by the $SU(3)_F$ octet of light pseudoscalar mesons, which are the…
We show how the unitarized description of pion nucleon scattering within Heavy Baryon Chiral Perturbation Theory can be considerably improved, by a suitable reordering of the expansion over the nucleon mass. Within this framework, the…
A general strategy is described for deriving a constituent approximation to QCD, inspired by the constituent quark model and based on light-front quantization. Some technical aspects of the approach are discussed, including a mechanism for…