Lattice determination of the muon's anomalous magnetic moment

Introduction

On 4/7/2021, Fermilab announced the result of a two-decade-long investigation to determine the magnetic moment of the muon. By tradition, data-driven theoretical methods have been used for 50 years to calculate this magnetic moment.

Discrepancies in Findings

Interestingly, in the last 20 years, growing discrepancies were noted between theoretical and experimental findings. In the literature, the result obtained by using the data-driven method is called the “consensus value” - and it is 4.2 sigma away from the combined experimental result.

This 4.2-sigma discrepancy was interpreted by many physicists as a sign of new physics with a new and unknown force. Consequently, hundreds of papers appeared in the last few months to explain the 4.2-sigma tension by some form of new physics.

Exciting Prospects for Theoretical Physics

For theoreticians, this is an extremely exciting situation because even better experimental results are expected in the next 1 to 5 years, which might further increase the tension between experiment and theory.

Proposed Approach

I propose a completely different and much more fundamental theoretical approach: lattice Quantum Chromodynamics (QCD). Within this new approach, I can reach better accuracies than those of the traditional approach.

Furthermore, my innovative approach uses far fewer experimental inputs, reducing the effects of uncertainties associated with input.

Objectives

The objective of the present application is to show unambiguously that either:

1. There is no new force, and the experimental results are actually in agreement with the Standard Model of particle physics, or
2. Confirm the existence of new physics with a high confidence level.

Methodology

To that end, a very large-scale lattice Quantum Chromodynamics approach will be applied using supercomputers to yield the muon's magnetic moment with the unprecedented precision of 10^-10 level of accuracy.

Conclusion

The success of this project will open a new window for high precision lattice Quantum Chromodynamics and put a final word on the two-decade-old mystery around the muon's magnetic moment.