Angular distribution of electrons in neutrinoless double-beta decay and new physics

For neutrinoless double-beta decay caused by the exchange of light Majorana neutrinos, an expression for the differential width with respect to the angle between the final-electron momenta is obtained on the basis of a Lorentz-invariant effective Lagrangian of the general form. The shape of this angular distribution is analyzed within various extensions of the Standard Model that allow this process-in particular, within theories that involve Majorana super partners and (or) right-handed currents. The angular correlation coefficient for electrons as a function of the mass of the right-handed W boson and the effective Majorana neutrino mass in the decay of the 76Ge nucleus is considered within the model involving left-right symmetry