Paper detail

Majorana CP-violating phases in neutrino-antineutrino oscillations and other lepton-number-violating processes

If the massive neutrinos are identified to be the Majorana particles via a convincing measurement of the neutrinoless double beta (0νββ) decay, how to determine the Majorana CP-violating phases in the 3 x 3 lepton flavor mixing matrix U will become a desirable experimental question. The answer to this question is to explore all the possible lepton-number-violating (LNV) processes in which the Majorana phases really matter. In this paper we carry out a systematic study of CP violation in neutrino-antineutrino oscillations, whose CP-conserving parts involve six independent 0νββ-like mass terms <m>_{αβ} and CP-violating parts are associated with nine independent Jarlskog-like parameters V^{ij}_{αβ} (for α, β= e, μ, τand i, j = 1, 2,3). With the help of current neutrino oscillation data, we analyze the sensitivities of |<m>_{αβ}| and V^{ij}_{αβ} to the three CP-violating phases of U, and illustrate the salient features of six independent CP-violating asymmetries between ν_α\to \barν_βand \barν_α\to ν_βoscillations. As a by-product, the effects of the CP-violating phases on the LNV decays of doubly- and singly-charged Higgs bosons are reexamined by taking account of the unsuppressed value of θ_{13}. Such CP-conserving LNV processes can be complementary to the possible measurements of neutrino-antineutrino oscillations in the distant future.