CP Violation in Antineutrino-Electron Elastic Scattering

Elastic scattering of transversely polarized electron antineutrino beam off unpolarized electrons can be used to detect the CP-violating effects by measuring the azimuthal asymmetry of recoil electrons caused by the interference terms between the standard vector $c_{V}^{L}$, axial $c_{A}^{L}$ couplings of left-chirality antineutrinos and exotic scalar $c_{S}^{R}$ coupling of right-chirality ones in the differential cross section. It would be a positive evidence for the existence of the exotic antineutrino states. Moreover, we also show that the differential cross section for the $\overline{\nu} e^-$ scattering can be obtained from the one for the $\nu e$ scattering, if one makes the substitution $c_{T}^{R} \to -c_{T}^{R}$, $c_{A}^{L} \to -c_{A}^{L}$, ${\bf q}\to -{\bf q}$, {\boldmath \hat{\eta}_{\nu}}\to -{\boldmath \hat{\eta}_{\nu}}.