New Test of Lorentz Invariance Using the MICROSCOPE Space Mission

Area of Science:

• Fundamental Physics
• Gravitational Physics
• Cosmology

Background:

• Tests of the universality of free fall probe fundamental physics principles.
• The Standard Model Extension (SME) provides a framework for describing potential violations of Lorentz symmetry.
• Lorentz violation in matter-gravity couplings could manifest as differential acceleration of test bodies.

Purpose of the Study:

• To search for Lorentz violation in matter-gravity couplings using data from the MICROSCOPE space mission.
• To set new constraints on specific Lorentz-violating Standard Model Extension (SME) coefficients.
• To improve upon existing experimental limits for these coefficients.

Main Methods:

• Analysis of data from five measurement sessions of the MICROSCOPE space mission, spanning one year.
• Utilizing the T-SAGE instrument to search for a specific signature of Lorentz violation dependent on Earth's orbital velocity and rotation.
• Applying statistical methods to constrain linear combinations of SME coefficients.

Main Results:

• No evidence for a signature of Lorentz violation in matter-gravity couplings was detected.
• New, stringent constraints were placed on linear combinations of SME coefficients, improving previous results by 1-2 orders of magnitude.
• Independent linear combinations of coefficients were derived, enhancing the diversity of available experimental constraints.

Conclusions:

• The MICROSCOPE experiment provides the tightest constraints to date on certain Lorentz-violating matter-gravity couplings.
• The results contribute to the ongoing effort to test fundamental symmetries of nature.
• The improved and diverse set of constraints pave the way for future decorrelation of individual SME coefficients.