1997/01/27 by Torben Hannah · 1 citation
Mathematics · Physics and Astronomy · #Amplitude #Black Holes and Theoretical Physics #Chiral perturbation theory #Classical mechanics #Geometry #Inverse #Mathematical analysis #Mathematical physics #Mathematics #Particle physics theoretical and experimental studies #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Quantum Chromodynamics and Particle Interactions #Quantum electrodynamics #Quantum mechanics #hep-ph
paper · pdf · doi:10.1103/physrevd.55.5613
published as Phys.Rev.D55:5613-5626,1997 · 27 pages, 10 figs, uses REVTeX and epsfig.sty, to appear in Phys. Rev. D
arxiv created 1997/01/27 · openalex publication_date 1997/05/01 · arxiv updated 2014/11/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The inverse amplitude method is analyzed to two-loop order in the chiral expansion in the case of \ensuremathπ\ensuremathπ scattering and the pion form factors. The analysis is mainly restricted to the elastic approximation but the possible extension to the inelastic case is also discussed in some detail. It is shown how the two-loop approach improves the inverse amplitude method applied to one-loop order in the chiral expansion. For both \ensuremathπ\ensuremathπ scattering and the pion form factors, it is in fact found that the inverse amplitude method to two-loop order agrees remarkably well with the experimental data up to energies where inelasticities become essential. At somewhat lower energies, the two-loop approach compares well with the one-loop approximation, and in the threshold region they both agree with chiral perturbation theory. This suggests that the inverse amplitude method is indeed a rather systematic way of improving chiral perturbation theory order by order in the chiral expansion.