Search for Lorentz invariance and CPT violation with the MINOS far detector

Area of Science:

• Particle Physics
• Astrophysics
• Cosmology

Background:

• The Standard Model Extension (SME) framework describes potential violations of Lorentz and CPT symmetry.
• Neutrino oscillations are a well-established phenomenon, but perturbative effects are not yet detected.
• Sidereal modulation in neutrino detection could indicate new physics beyond the Standard Model.

Purpose of the Study:

• To search for a sidereal modulation in the neutrino rate using data from the MINOS far detector.
• To test for evidence of Lorentz and CPT violation within the SME framework.
• To set improved upper limits on SME coefficients related to neutrino sector effects.

Main Methods:

• Analysis of neutrino event data collected by the MINOS far detector.
• Application of statistical methods to search for a sidereal time-dependent signal.
• Comparison of observed neutrino rates with predictions from Standard Model physics and SME extensions.

Main Results:

• No statistically significant sidereal modulation was detected in the MINOS far detector neutrino rate.
• The study established new upper limits on the magnitudes of Lorentz and CPT violating coefficients.
• These new limits represent a significant improvement (factors of 20-510) over previous best limits.

Conclusions:

• The absence of a sidereal signature places stringent constraints on Lorentz and CPT violation in the neutrino sector.
• The findings do not support the existence of detectable perturbative effects on neutrino oscillations due to SME parameters.
• Improved experimental sensitivity in neutrino physics continues to probe fundamental symmetries of spacetime.