A study of the gamma* - f0(980) transition form factors

TL;DR

This paper models the gamma* - f0(980) transition form factors assuming a quark-antiquark structure for the meson, compares theoretical predictions with experimental data, and discusses the need for power corrections and meson mixing effects.

Contribution

It introduces a quark-antiquark based wave function for the f0(980) meson and analyzes its transition form factors against recent experimental data.

Findings

Collinear approximation is insufficient at the momentum transfer range studied.

Power corrections related to quark transverse moment effects are likely necessary.

Mixing between f0(980) and sigma(500) mesons is briefly considered.

Abstract

The spin wave function of the f0(980)-meson is constructed under the assumption that the meson is dominantly a quark-antiquark state. This wave function is used in a calculation of the gamma* - f0 transition form factors. In the real-photon limit the results for the transverse form factor are compared to the large momentum transfer data measured by the BELLE collaboration recently. It turns out that, for the momentum-transfer range explored by BELLE, the collinear approximation does not suffer, power corrections to it, modeled as quark transverse moment effects, seem to be needed. Mixing of the f0 with the sigma(500) is also briefly discussed.