Experimental Measurements of the Muon $g-2$ and Searches for Charged Lepton Flavor Violation in the Muon Sector

TL;DR

This paper reviews recent experimental efforts in muon physics, focusing on the precise measurement of the muon g-2 and searches for charged lepton flavor violation, which could reveal physics beyond the Standard Model.

Contribution

It provides a comprehensive overview of recent results and the current status of muon g-2 measurements and charged lepton flavor violation searches, highlighting their significance for new physics.

Findings

Muon g-2 measurements show deviations from the Standard Model.

Upcoming experiments will probe new physics at mass scales up to 10^4 TeV/c^2.

Muon experiments continue to be crucial for testing fundamental physics theories.

Abstract

Since its discovery, the muon has proven to be an invaluable probe of the Standard Model (SM). Muons are readily available in tertiary beams in facilities around the world. They do not decay hadronically and have a lifetime of a few $\mu$ s; consequently, muon experiments offer clean, high-statistics environments to make precision measurements and search for new physics that could appear through deviations from the SM expectation. The 2020s have seen a renaissance in muon physics highlighted by the high-profile results from the Fermilab Muon $g - 2$ experiment which continues to provide successive measurements of the muon's anomalous magnetic moment with world-leading precision. In addition, a suite of experiments is coming online to search for new physics in the form of charged lepton flavor violation in the muon sector. These experiments will probe effective mass scales of new physics up to $10^4$ TeV/c$^2$, far beyond the reach of direct searches at colliders. This article explores the motivations, recent results, and status of these experiments.