2009/11/05 by L. Roca, E. Oset
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.81.014010
published as Phys.Rev.D81:014010,2010
arxiv created 2009/11/05 · openalex publication_date 2010/01/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We make a theoretical study of the charge and forward-backward pion asymmetries in the e+e^\ensuremath-\ensuremath→\ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathγ process on and off the \ensuremathφ resonance energy. These observables are rather sensitive to the inner details of the theoretical models to describe the reaction. In addition to the standard implementation of the initial state radiation and the bremsstrahlung contribution to the final state radiation, we use the techniques of the chiral unitary approach to evaluate the contribution from the mechanisms of \ensuremathφ decay into \ensuremathπ+\ensuremathπ^\ensuremath-\ensuremathγ. This contribution involves the implementation of final state interaction from direct chiral loops, the exchange of vector and axial-vector resonances and the final state interaction through the consideration of the meson-meson unitarized amplitudes, which were found important in a previous work describing the \ensuremathφ\ensuremath→\ensuremathπ\ensuremathπ\ensuremathγ. We find a good reproduction of the experimental data from KLOE for the forward-backward asymmetry, both at the \ensuremathφ peak and away from it. We also make predictions for the angular distributions of the charge asymmetry and show that this observable is very sensitive to the chiral loops involved in \ensuremathφ radiative decay.