The MTV Experiment: from T-violation To Lorentz-violation

The MTV (Mott Polarimetry for T-Violation) experiment is running at TRIUMF-ISAC (Isotope Separator and ACcelerator), searching for a large T violation in polarized Li-8 beta decay via measurements of the triple vector correlation, R, in the beta decay rate function. The left/right backward scattering asymmetry of Mott scattering from a thin metal foil is measured using an electron tracking detector including a cylindrical drift chamber (CDC). To achieve 10-ppm precision in the Mott scattering asymmetry, we performed multiple studies on the expected systematic effects. The sources of the systematics have been identified and calibration systems have been developed to evaluate the fake effects. The first physics data was collected in 2016 and significantly improved on the result of our previous measurement, which achieved 100-ppm precision in 2010 using the first generation detector (planer drift chamber) at TRIUMF. The data measurement status, together with the results of the systematics studies, is described here. In addition to the T violation, we are preparing to test the Lorentz invariance in the weak sector via our Mott analyzer system. Unexplored Lorentz violating correlations can be tested using the MTV experimental setup. The testing principle and preparation status are also described here.