Search for Lorentz and CPT Violation Effects in Muon Spin Precession

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 $\hat{I}”\ddot{I}{‰}_a$ (=$\ddot{I}{‰}_a^{\hat{I}{¼}^{+}}-\ddot{I}{‰}_a^{\hat{I}{¼}^{-}}$); and a sidereal variation of $\ddot{I}{‰}_a^{\hat{I}{¼}^{\pm }}$. 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; $(m_{\hat{I}}¼d_{Z0}+H_{XY})=(1.8\pm 6.0\times 10^{-23})$ GeV; and the 95% confidence level limits ${\check{b}}_{\perp }^{\hat{I}{¼}^{+}}<1.4\times 10^{-24}$ GeV and ${\check{b}}_{\perp }^{\hat{I}{¼}^{-}}<2.6\times 10^{-24}$ GeV.

5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestions