Related papers: Pion Decay
The pattern of chiral symmetry breaking is exploited to compute vector and axial-vector pion matrix elements in a uniform magnetic field. Our results are model independent, and thereby constitute low-energy theorems that must be obeyed by…
In these proceedings we illustrate that light, very weakly interacting particles can arise naturally from physics which is fundamentally connected to very high energy scales. Searching for them therefore may give us interesting new insights…
We study aspects of the pion condensation in two-flavor neutral quark matter using the Nambu--Jona-Lasinio model of QCD at finite density. We investigate the role of electric charge neutrality, and explicit symmetry breaking via quark mass,…
The interest, the status and the perspectives of various experiments in neutron and nuclear beta-decay, muon-decay and pion-decays are discussed. The talk is segmented into a discussion of the decay-rates and of the energy-spectra and…
As increased statistics and new ensembles with light pions have become available within the CLS effort, we complete previous work by inspecting the chiral behaviour of the pion decay constant. We discuss the validity of Chiral Perturbation…
Quantum Chromodynamics is the theory of strong interactions. It has been shown during the last decades that it describes correctly most of the properties of hadrons at high energy. The most distinctive feature of the theory is the…
We consider weak decays of heavy hadrons (bottom and charmed) where the heavy quark acts as a spectator. Theses decays are heavily phase-space suppressed but may become experimentally accessible in the near future. These decays are…
We review the foundations as well as a number of important applications of light-cone dynamics. Topics covered are: relativistic particle dynamics, reparametrization invariance, Dirac's front form, light-cone quantization of fields via…
The past fifty years have seen the emergence of a new field of research in physics, the study of matter at extreme temperatures and densities. The theory of strong interactions, quantum chromodynamics (QCD), predicts that in this limit,…
Pion decay width in a uniform magnetic background, constructed within chiral perturbation theory, is compared with lattice QCD for which results are available in the muon channel. While the results are consistent for large magnetic fields,…
We provide a perspective on studies aimed at observing the transition between hadronic and quark-gluonic descriptions of reactions involving light nuclei. We begin by summarizing the results for relatively simple reactions such as the pion…
We discus the role of QCD (Quantum Chromodynamics) to low energy phenomena involving the color-spin symmetry of the quark model. We then combine it with orbital and isospin symmetry to obtain wave functions with the proper permutation…
The perturbative QCD approach to quarkonium decay into a photon and hadrons is reconsidered. It is shown that a consistent treatment within perturbative QCD calls for the introduction of a fragmentation contribution which has been neglected…
High energy heavy ion collisions create quark gluon plasmas that behave like almost perfect fluids. Very similar features to those that led to this insight have also been observed in experimental data from collisions of small systems,…
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…
By exploring possible physical sense of notions, structures, and logic in a class of noncommutative geometries, we try to unify the four fundamental interactions within an axiomatic quantum picture. We identify the objects and algebraic…
Recent developments in studies of multiparticle correlations in high energy particle collisions are reviewed. Both experimental data and theoretical results in quantum chromodynamics are discussed. Application of the developed methods to…
We develop a relativistic quark model for pion structure, which incorporates the non-trivial structure of the vacuum of Quantum Chromodynamics as modelled by instantons. Pions are boundstates of quarks and the strong quark-pion vertex is…
The general features of quark and pion condensation in dense quark matter with flavor asymmetry have been considered at finite temperature in the presence of a chromomagnetic background field modelling the gluon condensate. In particular,…
The exact QCD is one of the cornerstones of particle physics. Hence it would appear that there should exist no physical situation where a broken version of QCD may have any relevance. However, here I shall show that a spontaneously broken…