We evaluate the light-quark meson contributions to three exact light-by-light scattering sum rules in light of new data by the Belle Collaboration, which recently has extracted the transition form factors of the tensor meson f2(1270) as well as of the scalar meson f0(980). We confirm a previous finding that the η,η′ and helicity-2 f2(1270) contributions saturate one of these sum rules up to photon virtualities around 1 GeV2. At larger virtualities, our sum rule analysis shows an important contribution of the f2(1565) meson and provides a first empirical extraction of its helicity-2 transition form factor. Two further sum rules allow us to predict the helicity-0 and helicity-1 transition form factors of the f2(1270) meson. Furthermore, our analysis also provides an update for the scalar and tensor meson hadronic light-by-light contributions to the muon's anomalous magnetic moment.
@article{arxiv.1611.04646,
title = {Light-by-light scattering sum rules in light of new data},
author = {Igor Danilkin and Marc Vanderhaeghen},
journal= {arXiv preprint arXiv:1611.04646},
year = {2017}
}