# g-2 short study and discussion

The Muon g-2 experiment measures the magnetic moment of the muon with high precision. The results are, well, interesting.

Images courtesy of Fermi National Accelerator Laboratory,

## Workshop Group Tutorial for Teachers

Questions

1. What are magnetic moment (hyperphysics) and gyromagmnetic ratio (Almost Complex Structure)?
2. How do these show up for a small charged particle moving in a magnetic field? Time for a crazy human trick!
3. What do we mean by g-2? (Hint: It is not 7.81 m/s2.)
4. The theoretical value of g, according to the Standard Model, is g = 2.00233183620(86).
• According to QED, g = 2. The remaining decimals are from QCD and the Standard Model.
• To get the anomalous magnetic moment, aμ first get the difference between the full theoretical value of g and the QED value of g, which we'll call gQED. Then divide by gQED. In (no) other words, aμ = (g - gQED)/gQED = (g-2)/2.
• Can you find the theoretical value of  the anomalous magnetic moment, aμ?
5. Now let's make sense of the chart below from Fermilab.

In case you missed the calculation, theoretical aμ = 0.00116591810(43).

Resources:

Probing Deeper: