We consider the consequences for future neutrino factory experiments of small $\mathrm{CPT}$-odd interactions in neutrino oscillations. The ${\nu }_{\mu }\to {\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_{\mu }$ survival probabilities at a baseline $L=732\mathrm{}\mathrm{km}$ can test for $\mathrm{CPT}$-odd contributions at orders of magnitude better sensitivity than present neutrino sector limits. Interference between the $\mathrm{CPT}$-violating interaction and $\mathrm{CPT}$-even mass terms in the Lagrangian can lead to a resonant enhancement of the oscillation amplitude. For oscillations in matter, a simultaneous enhancement of both neutrino and antineutrino oscillation amplitudes is possible.

• Received 19 May 2000

DOI:https://doi.org/10.1103/PhysRevLett.85.5055