Electromagnetic structure and weak decay of pseudoscalar mesons in a light-front QCD-inspired model

We study the scaling of the $^3S_1-^1S_0$ meson mass splitting and the pseudoscalar weak decay constants with the mass of the meson, as seen in the available experimental data. We use an effective light-front QCD-inspired dynamical model regulated at short-distances to describe the valence component of the pseudoscalar mesons. The experimentally known values of the mass splittings, decay constants (from global lattice-QCD averages) and the pion charge form factor up to 4 [GeV/c]$^2$ are reasonably described by the modelComment: 27 Pages, 7 eps figures,use revtex

Exactly Solvable Models of Interacting Spin-s Particles in one-dimension

We consider the exact solution of a many-body problem of spin-$s$ particles interacting through an arbitrary U(1) invariant factorizable $S$-matrix. The solution is based on a unified formulation of the quantum inverse scattering method for an arbitrary $(2s+1)$-dimensional monodromy matrix. The respective eigenstates are shown to be given in terms of $2s$ creation fields by a general new recurrence relation. This allows us to derive the spectrum and the respective Bethe ansatz equations.Comment: 10 pages, plain late

Weak decay constant of pseudscalar meson in a QCD-inspired model

We show that a linear scaling between the weak decay constants of pseudoscalar and the vector mesons masses is supported by the available experimental data. The decay constant scale as $f_m/f_{pi}=M_V/M_{\rho}$ (f_m is decay constant and M_V vector meson ground state mass). This simple form is justified within a renormalized light-front QCD-inpired model for quark-antiquark bound states.Comment: 4 pages, use revtex style. To appear "Brazilian Journal of Physics (2003)

Complex bounds for multimodal maps: bounded combinatorics

We proved the so called complex bounds for multimodal, infinitely renormalizable analytic maps with bounded combinatorics: deep renormalizations have polynomial-like extensions with definite modulus. The complex bounds is the first step to extend the renormalization theory of unimodal maps to multimodal maps.Comment: 20 pages, 3 figure

Phase Fluctuations and Vortex Lattice Melting in Triplet Quasi-One-Dimensional Superconductors at High Magnetic Fields

Assuming that the order parameter corresponds to an equal spin triplet pairing symmetry state, we calculate the effect of phase fluctuations in quasi-one-dimensional superconductors at high magnetic fields applied along the y (b') axis. We show that phase fluctuations can destroy the theoretically predicted triplet reentrant superconducting state, and that they are responsible for melting the magnetic field induced Josephson vortex lattice above a magnetic field dependent melting temperature Tm.Comment: 4 pages (double column), 1 eps figur

Top-BESS model and its phenomenology

We introduce the top-BESS model which is the effective description of the strong electroweak symmetry breaking with a single new SU(2)_L+R triplet vector resonance. The model is a modification of the BESS model in the fermion sector. The triplet couples to the third generation of quarks only. This approach reflects a possible extraordinary role of the top quark in the mechanism of electroweak symmetry breaking. The low-energy limits on the model parameters found provide hope for finding sizable signals in the LHC Drell-Yan processes as well as in the s-channel production processes at the ILC. However, there are regions of the model parameter space where the interplay of the direct and indirect fermion couplings can hide the resonance peak in a scattering process even though the resonance exists and couples directly to top and bottom quarks.Comment: published in Physical Review D, minor changes in text, 21 pages, 37 figure

Nonzero orbital angular momentum superfluidity in ultracold Fermi gases

We analyze the evolution of superfluidity for nonzero orbital angular momentum channels from the Bardeen-Cooper-Schrieffer (BCS) to the Bose-Einstein condensation (BEC) limit in three dimensions. First, we analyze the low energy scattering properties of finite range interactions for all possible angular momentum channels. Second, we discuss ground state ($T = 0$) superfluid properties including the order parameter, chemical potential, quasiparticle excitation spectrum, momentum distribution, atomic compressibility, ground state energy and low energy collective excitations. We show that a quantum phase transition occurs for nonzero angular momentum pairing, unlike the s-wave case where the BCS to BEC evolution is just a crossover. Third, we present a gaussian fluctuation theory near the critical temperature ($T = T_{\rm c}$), and we analyze the number of bound, scattering and unbound fermions as well as the chemical potential. Finally, we derive the time-dependent Ginzburg-Landau functional near $T_{\rm c}$, and compare the Ginzburg-Landau coherence length with the zero temperature average Cooper pair size.Comment: 28 pages and 24 figure