Related papers: Chiral Expansion Theory at Vector Meson Scale
After describing the SU(2) linear sigma model (L$\sigma$M), we dynamically generate it using the B.W. Lee null tadpole sum (characterizing the true vacuum) together with the dimensional regularization lemma. Next we generate the…
We study the octet SS-PP correlator within resonance chiral theory up to the one-loop level, i.e., up to next-to-leading order in the 1/Nc expansion. We will require that our correlator follows the power behaviour prescribed by the operator…
We present a brief account of the developments in the description of light meson resonances using unitarized extensions of the Chiral Perturbation Theory series, both in energy and temperature. In particular, we describe how these methods…
We study the mass, width and couplings of the lightest vector multiplet. Effective field theories based on chiral symmetry and a 1/N_C counting are adopted in order to describe the vector form factor associated to the two-pseudoscalar…
The Bethe-Salpeter equation restores exact elastic unitarity in the s- channel by summing up an infinite set of chiral loops. We use this equation to show how a chiral expansion can be undertaken by successive approximations to the…
We consider the low energy effective action of QCD below the chiral symmetry breaking scale, including, in Wilson's spirit, all operators of dimensionality less or equal to 6 which can be built with quark and chiral fields. The effect of…
Based on an effective Lagrangian which combines chiral SU(3) dynamics with vector meson dominance, we have developed a model for the forward vector meson-nucleon scattering amplitudes. We use this as an input to calculate the low energy…
Meson transition amplitudes of the vector, axial-vector, and tensor quark currents are analyzed within dispersion formulation of the constituent quark model. The form factors in the decay region are given by relativistic double spectral…
Using the Resonance Chiral Theory Lagrangian, we perform a calculation of the vector form factor of the pion at the next-to-leading order (NLO) in the 1/N(C) expansion. Imposing the correct QCD short-distance constraints, one fixes the…
Within the resonance chiral effective theory we study the dressed propagators of the spin-1 fields, as arise from a Dyson-Schwinger resummation perturbatively constructed from loop diagrams with absorptive contributions in the s-channel. We…
We present the first direct evaluation of DI = 3/2 K -> pi pi matrix elements with the aim of determining all the low-energy constants at NLO in the chiral expansion. Our numerical investigation demonstrates that it is indeed possible to…
We calculate the vacuum-expectation-value, the meson mass and the meson decay constant to next-to-next-to-leading-order in the chiral expansion for QCD-like theories with general $N_F$ degenerate flavours for the cases with a complex…
We formulate the expansion for the mass of the nucleon as a function of pion mass within chiral perturbation theory using a number of different ultra-violet regularisation schemes; including dimensional regularisation and various…
The properties of mesonic resonances can be calculated in terms of the low-energy coefficients of chiral perturbation theory (chiPT) by extending unitarized chiPT to higher energies. On the other hand these low-energy coefficients can be…
We discuss how the $1/N_c$ expansion and the chiral random matrix theory ($\chi$RMT) can be used in the study of large-$N_c$ gauge theories. We first clarify the parameter region in which each of these two approaches is valid: while the…
Effective Chiral Lagrangian is derived from QCD in the framework of Field Correlator Method. It contains the effects of both confinement and chiral symmetry breaking due to a special structure of the resulting quark mass operator. It is…
The $s-$wave meson-baryon scattering is analyzed for the strangeness S=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been considered: $\pi N$, $\eta N$, $K \Lambda$, $K \Sigma$. The…
Chiral perturbation theory (CPT), the low-energy effective theory of QCD, can be used to describe QCD observables in the low-energy region in a model-independent way. At any given order in the chiral expansion, CPT introduces a finite…
I discuss the properties of pions in ``partially quenched'' theories, i.e. those in which the valence and sea quark masses, $m_V$ and $m_S$, are different. I point out that for lattice fermions which retain some chiral symmetry on the…
The scalar, isovector meson propagator is analyzed in quenched QCD, using the MQA pole-shifting ansatz to study the chiral limit. In addition to the expected short-range exponential falloff characteristic of a heavy scalar meson, the…