Related papers: Large Nc and Chiral Dynamics
This work implements the combined BChPT and 1/Nc expansions for pion-nucleon elastic scattering. The effective theory is based on the baryon sector dynamical spin-flavor SU(4) symmetry emergent in the large Nc limit, whose breaking is…
As was shown by Leutwyler and Smilga, the fact that chiral symmetry is broken and the existence of a effective finite volume partition function leads to an infinite number of sum rules for the eigenvalues of the Dirac operator in QCD. In…
We suggest the idea, supported by concrete calculations within chiral models, that the critical endpoint of the phase diagram of Quantum Chromodynamics with three colors can be detected, by means of Lattice simulations of grand-canonical…
It is shown that the low energy coefficients of the next-to-leading order (NLO) chiral perturbation theory needed to determine $\Delta I=1/2$, $K\to\pi\pi$ decay amplitudes can be fixed by calculating $K\pi\to\pi$ amplitudes on lattice.…
Weinberg's theorem for \pi-\pi scattering, including the Adler zero at threshold in the chiral limit, is analytically proved for microscopic quark models that preserve chiral symmetry. Implementing Ward-Takahashi identities, the isospin 0…
We investigate the chiral phase transition at finite temperature (T) in colour SU(Nc=3) Quantum Chromodynamics (QCD) with six species of fermions (Nf=6) in the fundamental representation by using lattice QCD with improved staggered…
We study the critical properties of net-baryon-number fluctuations at the chiral restoration transition in a medium at finite temperature and net baryon density. The chiral dynamics of quantum chromodynamics (QCD) is modeled by the…
Explicit chiral symmetry breaking is a natural feature of many QCD inspired models with multi-quark interactions. To carry out the 1/N expansion of these theories, one integrates over the quark fields. In the process of calculating the…
We present technical details of the evaluation of the elastic pi-pi scattering amplitude to two loops in chiral perturbation theory. In particular, we elaborate on the renormalization procedure at the two-loop order and on the evaluation of…
The Chiral Quark-Soliton Model of nucleons is based on two ideas: 1) the major role of spontaneous chiral symmetry breaking in hadron physics and 2) the relevance of the large number of colours limit for the real world. In these lectures I…
We present a lattice calculation of the low energy constants of QCD with $N_c=3$, 4 and 5 colors and $N_f=2$ flavors of degenerate mass fermions. We fit data for the pseudoscalar meson mass, the pseudoscalar decay constant, and the Axial…
We study pion--nucleon scattering with a chiral lagrangian of pions, nucleons, and $\Delta$-isobars. The scattering amplitude is evaluated to one-loop $Q^3$ order, where $Q$ is a generic small momentum, using a new approach which is…
Matrix elements of six-quark operators are needed to extract new physics constraints from experimental searches for neutron-antineutron oscillations. This work presents in detail the first lattice quantum chromodynamics calculations of 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…
I review the large Nc behavior of light resonances generated from unitarized one-loop Chiral Perturbation Theory. In contrast with the rho or K*, the scalar behavior is at odds with a qqbar "dominant component". In fact, in the light scalar…
The chiral Lagrangian for Goldstone boson scattering is a power series expansion in numbers of derivatives. Each successive term is suppressed by powers of a scale, $\Lambda_\chi$, which must be less than of order $4\pi f/\sqrt{N}$ where…
We discuss the impact of chiral symmetry constraints on the quark-mass dependence of meson resonance pole positions, which are encoded in non-perturbative parametrizations of meson scattering amplitudes. Model-independent conditions on such…
The asymmetry in the angular distribution of n p --> d pi^0 due to Charge Symmetry Breaking is calculated using Heavy Baryon Chiral Perturbation Theory. Recent developments in power counting have proven successful in describing total cross…
We present the ingredients necessary for the determination of physical K->pi pi decay amplitudes for Delta I=3/2 transitions, from lattice simulations at unphysical kinematics and the use of chiral perturbation theory at next-to-leading…
We present for the first time a determination of the energy dependence of the isoscalar $\pi\pi$ elastic scattering phase-shift within a first-principles numerical lattice approach to QCD. Hadronic correlation functions are computed…