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

TL;DR

The paper explores the potential of the KLOE-2 experiment to precisely measure the pi0 decay width and transition form factor at low energies, which are crucial for understanding strong interactions and muon g-2 calculations.

Contribution

It demonstrates, via Monte Carlo simulations, that KLOE-2 can measure the pi0 decay width with better accuracy than current data and first-time measurement of the form factor at low Q^2.

Findings

Expected measurement accuracy for Gamma(pi0 to gamma gamma) at the percent level.

First measurement of the pi0 transition form factor at Q^2 ≤ 0.1 GeV^2.

Potential to improve understanding of hadronic light-by-light scattering in muon g-2.

Abstract

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.