Unitarity, chiral perturbation theory, and meson form factors

Abstract

The inverse-amplitude method is applied to the one-loop chiral expansion of the pion, kaon, and K l3 form factors. Since these form factors are determined by the same chiral low-energy constants, it is possible to obtain finite predictions for the inverse-amplitude method. It is shown that this method clearly improves one-loop chiral perturbation theory, and a very good agreement between the inverse-amplitude method and the experimental information is obtained. This suggests that the inverse-amplitude method is a rather systematic way of improving chiral perturbation theory. ͓S0556-2821͑96͒02619-7͔

Effective field theory description of the pion form factor

“…9,10,[19][20][21][22][23][24] The different ingredients we have used can in fact be found in the existing literature on the subject. However, it is only when one combines together all those physical informations that such a simple description of F (s) emerges.…”

Effects of Electrode Length on Capacitively Coupled External Electrode Fluorescent Lamps

“…In this paper we have used a more conventional [14,15,16] value for L 5 = (1.4 ± 0.5) × 10 −3 as compared to L 5 = 2.2 × 10 −3 from [48] because the latter one was obtained in the assumption of a very light scalar meson. However our analysis has made evident that the low-mass scalar quarkonium bound state should be quite heavy (m σ ∼ 1 GeV).…”

Study of the resummation of chiral logarithms in the exponentiated expression for the pion form factor

“…This fact does not occur in resummations based on the [0,1] Padé approximants like for instance those from the inverse amplitude method [4,5,6] or the Gounaris-Sakurai parametrization [3].…”

“…It applies a dispersion relation to F −1 , calculated with ChPT, instead of applying it to F , the form factor. It works better because the imaginary part of F −1 in the elastic case is a better approximation to data than just with F [4,5,6].…”