Measurement of the gamma gamma* --> eta and gamma gamma* --> eta' transition form factors

TL;DR

This paper measures the transition form factors for eta and eta' mesons in gamma gamma* interactions over a wide momentum transfer range using data from the BABAR detector, providing insights into meson structure.

Contribution

First measurement of gamma gamma* --> eta and eta' transition form factors over 4 to 40 GeV^2 using a large data sample from BABAR.

Findings

Transition form factors measured across a wide momentum transfer range.

Results provide new data for testing QCD predictions.

Analysis enhances understanding of meson internal structure.

Abstract

We study the reactions e+e- --> e+e- eta (eta') in the single-tag mode and measure the gamma gamma* --> eta (eta') transition form factors in the momentum transfer range from 4 to 40 GeV^2. The analysis is based on 469 fb-1 of integrated luminosity collected at PEP-II with the BABAR detector at e+e- center-of-mass energies near 10.6 GeV.