Eur. Phys. J. C 24, 535-545 (2002)
Four-pion production in e+e- annihilationG. Ecker and R. Unterdorfer
Institut für Theoretische Physik, Universität Wien, Boltzmanngasse 5, 1090 Vienna, Austria
(Received: 8 March 2002 / Published online: 14 June 2002 )
We calculate the processes and to O(p4) in the low-energy expansion of the standard model. The chiral amplitudes of O(p4) can be extended via resonance exchange to energies around 1 GeV. Higher-order effects have been included in the form of , a1 and double exchange and by performing a resummation of the pion form factor. The predicted cross sections and the branching ratios are in good agreement with the available data.
© Società Italiana di Fisica, Springer-Verlag 2002