Neutrino–antineutrino mass splitting in the Standard Model and baryogenesis

Abstract

On the basis of a previously proposed mechanism of neutrino-antineutrino mass splitting in the Standard Model, which is Lorentz and SU(2) × U (1) invariant but non-local to evade the CPT theorem, we discuss the possible implications of neutrino-antineutrino mass splitting on neutrino physics and baryogenesis. It is shown that non-locality within a distance scale of the Planck length, that may not be fatal to unitarity in a generic effective theory, can generate the neutrino-antineutrino mass splitting of the order of the observed neutrino mass differences, which is tested in oscillation experiments, and a nonnegligible baryon asymmetry depending on the estimate of sphaleron dynamics. The one-loop order induced electron-positron mass splitting in the Standard Model is shown to be finite and estimated at ∼10 −20 eV, well below the experimental bound <10 −2 eV. The induced CPT violation in the K -meson in the Standard Model is expected to be even smaller and well below the experimental bound |m K − mK | < 0.44 × 10 −18 GeV.

Parity-doublet representation of Majorana fermions and neutron oscillation

“…However, we mention that the relevant mass scale of the neutron oscillation is estimated at ϵ 1 ≤ 6 × 10 −24 eV and n − n mass splitting itself is constrained to be less than 10 −15 eV to observe the oscillation [6]. These values are not much different from the estimated mass difference ∼10 −20 eV of the electron and positron induced by the possible CPT breaking that is required to explain the small (2σ) mass difference of the observed Sun neutrino and reactor antineutrino as really arising from the Lorentz-invariant CPT breaking [16]. See also a recent paper [10].…”

“…The possible CPT violation in the hadron sector appears to be very small as is indicated by both experimental limit jm K − m K j < 0.44 × 10 −18 GeV [15] and a recent model study within an extension of the Standard Model [16]. However, we mention that the relevant mass scale of the neutron oscillation is estimated at ϵ 1 ≤ 6 × 10 −24 eV and n − n mass splitting itself is constrained to be less than 10 −15 eV to observe the oscillation [6].…”

“…The γ 0 -parity transformation maps a solution ψ þ ðx; ϵ 1 Þ with mass Mðϵ 1 Þ in (14) to another solution ψ − ðx; −ϵ 1 Þ with mass Mð−ϵ 1 Þ in (20) as is suggested by the broken parity symmetry relation in (16).…”

Neutrino–Antineutrino Mass Splitting in the Standard Model: Neutrino Oscillation and Baryogenesis

“…In short, we assume that every mass arises from the Higgs doublet, which has been discovered recently. One may add a hermitian non-local Higgs coupling with a real parameter µ to the above Lagrangian [2],…”

“…It may be interesting to incorporate CPT breaking in the neutrino mass sector of a minimal extension of the Standard Model. We incorporate, a)C, CP and CPT breaking, b)Lorentz invariance, c)SU(2)xU(1) gauge invariance, d)Non-locality within a distance scale of the Planck length, in our model of the neutrino-antineutrino mass splitting [2].…”