Dispersion Relation Analyses of Pion Form Factor, Chiral Perturbation Theory and Unitarized Calculations
نویسنده
چکیده
The Vector Pion form factor below 1 GeV is analyzed using experimental data on its modulus, the P-wave pion pion phase shifts and dispersion relation. It is found that causality is satisfied. Using dispersion relation, terms proportional to s 2 and s3 are calculated using the experimental data, where s is the momentum transfer. They are much larger than the one-loop and two-loop Chiral Perturbation Theory calculations. Unitarized model calculations agree very well with dispersion relation results. ∗unité propre 014 du CNRS
منابع مشابه
Taylor’s Series and Dispersion Relation Analyses of the Vector Pion Form Factor and their Comparison with Perturbative and Non Perturbative Calculations
The first three coefficients of the Taylor’s series expansion of the vevtor pion form factor as a function of the momentum transfer are evaluated using the experimental data on the pion form factor and the P-wave ππ phase shifts. The real part of the form factor as a function of energy is also calculated by dispersion relation. Comparisons there results with Chiral Perturbation Theory and unita...
متن کاملUnitarized ChPT Amplitudes and Crossing Symmetry Violation
Pion-pion scattering amplitude obtained from one-loop Chiral Perturbation Theory (ChPT) is crossing symmetric, however the corresponding partial-wave amplitudes do not respect exact unitarity relation. There are different approaches to get unitarized results from ChPT. Here we consider the inverse amplitude method (IAM) and, using the Roskies relations, we measure the amount of crossing symmetr...
متن کاملUnitarized chiral perturbation theory of hadrons
An exposition is made of recent developments using techniques of unitary chiral perturbation theory, UχPT , which allows one to extend predictions using chiral Lagrangians to higher energies than ordinary chiral perturbation theory, including the region of low lying mesonic and baryonic resonances, some of which are dynamically generated in the approach. Results for meson meson scattering, pion...
متن کامل0 Bethe - Salpeter Approach for Unitarized Chiral Perturbation Theory
Departamento de F́ısica Moderna Universidad de Granada E-18071 Granada, Spain (February 1, 2008) 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 in the two particle irreducible amplitude and the propagators accomplishing exact elastic unitarity at an...
متن کاملNature of the f0(600) scalar meson from its Nc dependence at two loops in unitarized chiral perturbation theory.
By using unitarized two-loop chiral perturbation theory partial waves to describe pion-pion scattering we find that the dominant component of the lightest scalar meson does not follow the qq dependence on the number of colors that, in contrast, is obeyed by the lightest vectors. The method suggests that a subdominant qq component of the f0(600) possibly originates around 1 GeV.
متن کامل