48,570 research outputs found
Reversors and Symmetries for Polynomial Automorphisms of the Plane
We obtain normal forms for symmetric and for reversible polynomial
automorphisms (polynomial maps that have polynomial inverses) of the plane. Our
normal forms are based on the generalized \Henon normal form of Friedland and
Milnor. We restrict to the case that the symmetries and reversors are also
polynomial automorphisms. We show that each such reversor has finite-order, and
that for nontrivial, real maps, the reversor has order 2 or 4. The normal forms
are shown to be unique up to finitely many choices. We investigate some of the
dynamical consequences of reversibility, especially for the case that the
reversor is not an involution.Comment: laTeX with 5 figures. Added new sections dealing with symmetries and
an extensive discussion of the reversing symmetry group
Light meson resonances from unitarized Chiral Perturbation Theory
We report on our recent progress in the generation of resonant behavior in
unitarized meson-meson scattering amplitudes obtained from Chiral Perturbation
Theory. These amplitudes provide simultaneously a remarkable description of the
resonance region up to 1.2 GeV as well as the low energy region, since they
respect the chiral symmetry expansion. By studying the position of the poles in
these amplitudes it is possible to determine the mass and width of the
associated resonances, as well as to get a hint on possible classification
schemes, that could be of interest for the spectroscopy of the scalar sector.Comment: Invited talk to the II International Workshop on Hadron Physics &
Effective Theories of Low Energy QCD. 25-29 September 2002. Coimbra. Portuga
Meson resonances from unitarized meson scattering at one loop in Chiral Perturbation Theory
We show the results for the scattering poles associated to the rho, f0, a0,
K*, sigma and kappa resonances in meson-meson scattering. Our amplitudes are
obtained from the complete one-loop meson-meson scattering amplitudes from
Chiral Perturbation Theory. Once unitarized with the Inverse Amplitude Method,
they describe remarkably well the data simultaneously in the low energy and
resonance regions up to 1.2 GeV, using low energy parameters compatible with
present determinations.Comment: To appear in the proceedings of the 5th International Conference on
``Quark confinement and the hadron spectrum'', held in Gargnano, Garda Lake,
Italy. 10-14th September 2002. 3 page
Unitarization of the complete meson-meson scattering at one loop in Chiral Perturbation Theory
We report on our one-loop calculation of all the two meson scattering
amplitudes within SU(3) Chiral Perturbation Theory, i.e. with pions, kaons and
etas. Once the amplitudes are unitarized with the coupled channel Inverse
Amplitude Method, they satisfy simultaneously the correct low-energy chiral
constraints and unitarity. We obtain a remarkable description of meson-meson
scattering data up to 1.2 GeV including the scattering lengths and seven light
resonances.Comment: To appear in the proceedings of QCD@work: International Workshop on
QCD: Theory and Experiment. Martina Franca (Italy) June 16-20. 200
Complete meson-meson scattering within one loop in Chiral Perturbation Theory: Unitarization and resonances
We review our recent one-loop calculation of all the two meson scattering
amplitudes within SU(3) Chiral Perturbation Theory, i.e. with pions, kaons and
etas. By unitarizing these amplitudes we are able to generate dynamically the
lightest resonances in meson-meson scattering. We thus obtain a remarkable
description of the meson-meson scattering data right from threshold up to 1.2
GeV, in terms of chiral parameters in good agreement with previous
determinations.Comment: 4 pages, To appear in the Proceedings of the IX International
Conference on Hadron Spectroscopy, HADRON2001, IHEP, Protvino, Russia, August
200
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