https://doi.org/10.1140/epjc/s10052-021-09513-x
Regular Article - Theoretical Physics
Short-distance constraints for the longitudinal component of the hadronic light-by-light amplitude: an update
1
Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland
2
Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
3
Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
Received:
5
July
2021
Accepted:
29
July
2021
Published online:
6
August
2021
We reassess the impact of short-distance constraints for the longitudinal component of the hadronic light-by-light amplitude on the anomalous magnetic moment of the muon, 
, by comparing different solutions that have recently appeared in the literature. In particular, we analyze the relevance of the exact axial anomaly and its impact on 
and conclude that it remains rather limited. We show that all recently proposed solutions agree well within uncertainties on the numerical estimate of the impact of short-distance constraints on , despite differences in the concrete implementation. We also take into account the recently calculated perturbative corrections to the massless quark loop to update our estimate and outline the path towards future improvements.
© The Author(s) 2021
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