A search for the violation of Lorentz invariance is performed with ttbar dilepton eμ final state at CMS, using 2016 and 2017 data. The Lorentz-violating signature is predicted as a modulation of the ttbar cross section with sidereal time. A differential measurement of the ttbar yield as a function of sidereal time is performed. The analysis also reports a measurement of Lorentz-violating Wilson coefficients within a dedicated Effective Field Theory, called the Standard Model Extension. This search can also be seen as a precision test of special relativity with the top quark, heaviest elementary particle at the LHC energy frontier.
