Muon g–2

Context: Newly published results of an international experiment hint at the possibility of new physics governing the laws of nature.

• The results of the experiment, which studied a subatomic particle called the muon, do not match the predictions of the Standard Model, on which all particle physics is based.

What is the Standard Model?

• The Standard Model is a rigorous theory that predicts the behaviour of the building blocks of the universe.
• It lays out the rules for six types of quarks, six leptons, the Higgs boson, three fundamental forces, and how the subatomic particles behave under the influence of electromagnetic forces.

What is MUON?

• The muon is one of the leptons.
• It is similar to the electron, but 200 times larger, and much more unstable, surviving for a fraction of a second.
• The experiment, called Muon g–2 (g minus two), was conducted at the US Department of Energy’s Fermi National Accelerator Laboratory (Fermilab).

What was this experiment about?

• The Muon g–2 experiment measured quantity relating to the muon, with greater accuracy.
• It sought to find out whether the discrepancy would persist, or whether the new results would be closer to predictions.
• Muon is unstable, they act as if they have a tiny internal magnet.
• In a strong magnetic field, the direction of this magnet “wobbles” — just like the axis of a spinning top.
• The rate at which the muon wobbles is described by the g-factor, the quantity that was measured.
• This value is known to be close to 2, so scientists measure the deviation from 2. Hence the name g–2.

https://indianexpress.com/article/explained/muon-g-2-landmark-study-challenges-rulebook-of-particle-physics-7265173/