TY  - JOUR
AU  - Holz, S.
AU  - Plenter, J.
AU  - Xiao, C. W.
AU  - Dato, T.
AU  - Hanhart, Christoph
AU  - Kubis, B.
AU  - Meißner, U.-G.
AU  - Wirzba, A.
TI  - Towards an improved understanding of ${\eta \rightarrow \gamma ^*\gamma ^*}$
JO  - The European physical journal / C
VL  - 81
IS  - 11
SN  - 1434-6044
CY  - Heidelberg
PB  - Springer
M1  - FZJ-2021-04254
SP  - 1002
PY  - 2021
AB  - We argue that high-quality data on the reaction e+e−→π+π−η will allow one to determine the doubly-virtual form factor η→γ∗γ∗ 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 the muon. When analyzing the existing data for e+e−→π+π−η for total energies squared k2>1GeV2, we demonstrate that the effect of the a2 meson provides a natural breaking mechanism for the commonly employed factorization ansatz in the doubly-virtual form factor Fηγ∗γ∗(q2,k2). However, better data are needed to draw firm conclusions.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000718113500001
DO  - DOI:10.1140/epjc/s10052-021-09661-0
UR  - https://juser.fz-juelich.de/record/902432
ER  -