Mirror model for sterile neutrinos

Sterile neutrinos are studied as subdominant contribution to solar neutrino physics. The mirror-matter neutrinos are considered as sterile neutrinos. We use the symmetric mirror model with gravitational communication between mirror and visible sectors. This communication term provides mixing between visible and mirror neutrinos with the basic scale μ=vEW2/MPl=2.5×10−6 eV, where vEW=174 GeV is the vacuum expectation value of the standard electroweak group and MPl is the Planckian mass. It is demonstrated that each mass eigenstate of active neutrinos splits into two states separated by small Δm2. Unsuppressed oscillations between active and sterile neutrinos (νa↔νs) occur only in transitions between each of these close pairs (“windows”). These oscillations are characterized by very small Δm2 and can suppress the flux and distort spectrum of pp-neutrinos in detectable way. The other observable effect is anomalous seasonal variation of neutrino flux, which appears in LMA solution. The considered subdominant neutrino oscillations νa↔νs can reveal itself as big effects in observations of supernova neutrinos and high-energy (HE) neutrinos. In the case of HE neutrinos they can provide a very large diffuse flux of active neutrinos unconstrained by the e–m cascade upper limit.