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Updated: Sep 27, 2026

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
Revised alpha4 term of lepton g-2 from the Feynman diagrams containing an internal light-by-light scattering
1Laboratory for Elementary Particle Physics, Cornell University, Ithaca, New York 14853, USA. tk@hepth.cornell.edu
Abstract:
The alpha(4) contribution to the lepton g-2 from a gauge-invariant set of 18 Feynman diagrams containing a light-by-light scattering subdiagram internally has been reevaluated by a method independent of the previous approach. Comparison of two methods revealed a program error in the first version. Correcting this error, the contributions of these 18 diagrams become -0.990 72(10)(alpha/pi)(4) and -4.432 43(58)(alpha/pi)(4) for the electron and muon g-2, respectively. The correction is not large enough to affect the comparison between theory and experiment for the muon g-2, but it does alter the inferred value for the fine structure constant alpha(-1) by 6 ppb.
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