CP Properties of Leptons within the Mirror Mechanism

Resumo

The formation of the quark and lepton mass matrices through intermediate states of heavy mirror fermions is able to reproduce basic observable qualitative properties of weak-mixing matrices—specifically, the Cabibbo—Kobayashi—Maskawa (CKM) matrix and the Pontecorvo—Maki—Nakagawa-Sakata (PMNS) matrix. The reproduction in question includes the hierarchy of the CKM matrix elements and a general form of the PMNS matrix, including the smallness of the neutrino mixing angle θ₁₃ and leads to extremely small neutrino masses. For leptons, these properties arise only if Standard Model neutrinos are Dirac particles and if the spectrum of their generations has an inverse character. In such a lepton system, the mechanism of spontaneous mirror-symmetry violation and the observed mass hierarchy of charged leptons (e, μ, and τ) specify the structure of the PMNS matrix and make it possible to estimate the complex-valuedness of its elements—that is, to assess the CP properties of leptons. In this case, the PMNS matrix does not involve Majorana phases, whereas its Dirac phase δ_CP corresponds to ∣ sin δ_CP ∣ that is substantially smaller than unity.