Related papers: Possible Extension of the Chiral Perturbation Theo…
We extend our previous formulation of low-energy QCD in terms of an effective lagrangian containing operators of dimensionality $d\le 6$ constructed with pseudoscalars and quark fields, describing physics below the scale of chiral symmetry…
The phenomena of confinement and dynamical chiral symmetry breaking are basic to understanding hadron observables. They can be explored using Dyson-Schwinger equations. The existence of a systematic, nonperturbative and symmetry preserving…
A new tool which combines chiral perturbation theory and unitarity in coupled channels is applied with success to the study of the meson-meson interaction, extending the theoretical predictions up to sqrt{s} = 1.2 GeV, hence improving…
Based on an effective chiral theory of pseudoscalar, vector, and axial-vector mesons, the coefficients of the chiral perturbation theory are predicted. There is no new parameter in these predictions.
Spontaneous chiral symmetry breaking is accepted to occur in low energy hadronic physics, resulting in the several successful theorems of PCAC. On the other hand scalar confinement is suggested both by the spectroscopy of hadrons and by the…
We discuss the vector meson masses within the context of Chiral Perturbation Theory performing an expansion in terms of the momenta, quark masses and 1/Nc. We extend the previous analysis to include isospin breaking effects and also include…
In the limit of vanishing up, down and strange quark masses, QCD exhibits a chiral symmetry. This symmetry is broken spontaneously to its vector subgroup, giving rise to Goldstone bosons. These acquire a small mass through the explicit…
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…
We present a brief review of recent attempts to construct effective theories to describe the breaking of the electroweak symmetry in extensions of the Standard Model with new strongly interacting dynamics around the TeV scale. Particular…
We present new results for the SU(3) "sextet model" with two flavors transforming according to the two-index symmetric representation of the gauge group. The simulations are performed using unimproved Wilson fermions. We measure the meson…
Chiral symmetry breaking patterns are investigated in the U_L(n)xU_R(n) meson model. It is shown that new classes of minima of the effective potential belonging to the center of the Lie algebra exist for arbitrary flavor number n. The true…
Spontaneous breaking of chiral symmetry in QCD has traditionally been inferred indirectly through low-energy theorems and comparison with experiments. Thanks to the understanding of an unexpected connection between chiral Random Matrix…
We extend the quark-meson coupling (QMC) model to incorporate chiral symmetry. The relationship between the QMC model and chiral perturbation theory is also discussed. The nuclear central potential is modified by the effect of internal…
The spontaneous symmetry breaking of a local chiral symmetry to its diagonal vector symmetry naturally realizes a complete geometrical structure more general than that of Yang-Mills (YM) theory, rather similar to that of gravity. A good…
Corrections to $K\rightarrow\pi\pi\pi$ induced by vector and scalar meson exchange are investigated within chiral perturbation theory.
The status of chiral perturbation theory in the meson sector is illustrated with several topical examples. The longtime discrepancy between theory and experiment for the charged pion polarizabilities has now been resolved in favour of the…
In this talk we briefly describe some basic elements of chiral perturbation theory, $\chi PT$, and how the implementation of unitarity and other novel elements lead to a better expansion of the $T$ matrix for meson meson and meson baryon…
We develop Chiral Perturbation Theory for chirally broken theories with fermions in two different representations of the gauge group. Any such theory has a non-anomalous singlet $U(1)_A$ symmetry, yielding an additional Nambu-Goldstone…
I review the status of chiral perturbation theory in the one-nucleon sector and give some predictions to be tested. I then discuss various methods to go to higher energies (inclusion of the Delta(1232), dispersion relations) and also to…
The Bethe-Salpeter equation is related to a generalized quantum-mechanical Hamiltonian. Instability of the presumed vacuum, indicated by a tachyon, is related to a negative energy eigenstate of this Hamiltonian. The variational method shows…