Theory Group Seminars

Lattice QCD computation of the muon magnetic moment

by Prof. Szabo Kalman (University of Wuppertal)

241 (Edificio C)


Edificio C


The muon is an elementary particle, a short-lived cousin of the electron. Since about 20 years the calculation of its magnetic moment disagrees with its measurement, indicating that a not-yet-known particle or force might be influencing the muon. An experiment at the Fermi National Accelerator Laboratory (FNAL,US) confirmed this puzzling discrepancy with an announcement in April 2021. The event received significant media attention. 

At the same time our group published a new ab-inito calculation, based on lattice formulation of quantum chromodynamics (lattice QCD), which challenged previous computations and brought the theoretical prediction closer to the experimental value. According to this result, no new forces or particles are neccessary to explain the FNAL and previous measurements.

Currently, the question if there is any new physics in the muon magnetic moment, is open. Since 2021 several new independent lattice QCD computations have appeared, there are updates of the old style theory approach, and also comparisons of the two approaches. In the meantime the FNAL experiment keeps on gathering new data.

The talk will give a review of these efforts with the main focus on our original lattice computation.

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