Search for Lorentz and CPT Violation Effects in Muon Spin Precession

TL;DR

This study searched for Lorentz and CPT violation effects in muon spin precession using the muon g-2 storage ring, setting new limits on related parameters with no significant violations observed.

Contribution

It provides the first experimental limits on Lorentz and CPT violation parameters in muon spin precession with high precision.

Findings

No significant Lorentz or CPT violation detected.

Set new upper limits on violation parameters.

Improved constraints on standard-model extension parameters.

Abstract

The spin precession frequency of muons stored in the $(g-2)$ storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero $\Delta\omega_{a}$ (=$\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}$); and a sidereal variation of $\omega_{a}^{\mu^{\pm}}$. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: $b_{Z} =-(1.0 \pm 1.1)\times 10^{-23}$ GeV; $(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23})$ GeV; and the 95% confidence level limits $\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24}$ GeV and $\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24}$ GeV.