On the possibility to measure the (pi0 to gamma gamma) decay width and the (gamma* gamma to pi0) transition form factor with the KLOE-2 experiment

D. Babusci, H. Czyz, F. Gonnella, S. Ivashyn, M. Mascolo, R. Messi, D. Moricciani, A. Nyffeler, G. Venanzoni, KLOE-2 Collaboration

Published 2011-09-12, updated 2012-02-24Version 2

A possibility of KLOE-2 experiment to measure the width Gamma(pi0 to gamma gamma) and the (pi0 gamma gamma*) form factor F(Q^2) at low invariant masses of the virtual photon in the space-like region is considered. This measurement is an important test of the strong interaction dynamics at low energies. The feasibility is estimated on the basis of a Monte-Carlo simulation. The expected accuracy for Gamma(pi0 to gamma gamma) is at a per cent level, which is better than the current experimental world average and theory. The form factor will be measured for the first time at Q^2 less or equal 0.1 GeV^2 in the space-like region. The impact of these measurements on the accuracy of the pion-exchange contribution to the hadronic light-by-light scattering part of the anomalous magnetic moment of the muon is also discussed.