TY  - JOUR
AU  - Holz, S.
AU  - Plenter, J.
AU  - Xiao, C. W.
AU  - Dato, T.
AU  - Hanhart, C.
AU  - Kubis, B.
AU  - Meissner, U. G.
AU  - Wirzba, A.
PY  - 2021
DA  - 2021//
TI  - Towards an improved understanding of eta -> gamma*gamma *
T2  - Eur. Phys. J. C
JO  - European Physical Journal C
SP  - 1002
EP  - 15pp
VL  - 81
IS  - 11
PB  - Springer
AB  - We argue that high-quality data on the reaction e(+)e(-) -> pi(+) pi(-) eta will allow one to determine the doubly-virtual form factor eta -> gamma*gamma* in a model-independent way with controlled accuracy. This is an important step towards a reliable evaluation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of themuon. When analyzing the existing data for e(+) e(-) -> pi(+) pi(-) eta for total energies squared k(2) > 1GeV(2), we demonstrate that the effect of the a(2) meson provides a natural breaking mechanism for the commonly employed factorization ansatz in the doubly-virtual form factor F-eta gamma*gamma* (q(2), k(2)). However, better data are needed to draw firm conclusions.
SN  - 1434-6044
UR  - https://arxiv.org/abs/1509.02194
UR  - https://doi.org/10.1140/epjc/s10052-021-09661-0
DO  - 10.1140/epjc/s10052-021-09661-0
LA  - English
N1  - WOS:000718113500001
ID  - Holz_etal2021
ER  -