Tests of the Lorentz invariance violation in double-beta decay

Abstract Testing the Lorentz invariance violation (LIV) double-beta decay (DBD) is an interesting, recently opened topic, currently under investigation. Theoretically, LIV can be induced in this process by coupling neutrinos to the countershaded operator in the Standard Model extension (SME) theory, particularly to its time-like component, and could manifest as small perturbations in the shape of the energy spectra of electrons. In the absence of observation of such perturbations, one can constrain the values of the oscillation-free (of) coefficient å o f ( 3 ) , that controlled the size of the LIV effects. Such investigations are currently been conducted in several DBD experiments and are based on theoretical predictions of the electron spectra and angular correlation between electrons in 2νββ decay. In this paper I first present some general considerations about DBD and then give a brief review of the current status of LIV searches in the study of this process.