Authors:	Chao, En-Hung Hudspith, Renwick J. Gérardin, Antoine Green, Jeremy R. Meyer, Harvey B.
Title:	The charm-quark contribution to light-by-light scattering in the muon (g − 2) from lattice QCD
Online publication date:	17-Apr-2023
Year of first publication:	2022
Language:	english
Abstract:	We compute the hadronic light-by-light scattering contribution to the muon g−2 from the charm quark using lattice QCD. The calculation is performed on ensembles generated with dynamical(u, d,s) quarks at the SU(3)f symmetric point with degenerate pion and kaon masses of around 415 MeV. It includes the connected charm contribution, as well as the leading disconnected Wick contraction, involving the correlation between a charm and a light-quark loop. Cutoff effects turn out to be sizeable, which leads us to use lighter-than-physical charm masses, to employ a broad range of lattice spacings reaching down to 0.039 fm and to perform a combined charm-mass and continuum extrapolation. We use the ηc meson to define the physical charm-mass point and obtain a final value of aHLbL,c μ = (2.8±0.5)×10−11, whose uncertainty is dominated by the systematics of the extrapolation. Our result is consistent with the estimate based on a simple charm-quark loop, whilst being free of any perturbative scheme dependence on the charm mass. The mixed charm–light disconnected contraction contributes a small negative amount to the final value.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik Helmholtz Institut Mainz
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-8919
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	The European physical journal : C, Particles and fields 82
Pages or article number:	664
Publisher:	Springer
Publisher place:	Berlin
Issue date:	2022
ISSN:	1434-6052
Publisher DOI:	10.1140/epjc/s10052-022-10589-2
Appears in collections:	DFG-491381577-D