Astrophysical Implications of the Mirror World with Broken Mirror Parity

Abstract

We discuss the physics of the mirror (shadow) world which is completely analogous to the visible one except that its `weak' scale is larger by one or two orders of magnitude than the weak scale in the standard model. The mirror neutrinos can mix the ordinary ones through the Planck scale induced higher order operators, which can help to reconcile the present neutrino puzzles that are the solar and atmospheric neutrino deficits, the recent LSND anomaly and the need in the $\sim$ eV mass neutrino as the hot dark matter. In particular, oscillation of $ν_e$ into its mirror partner $ν'_e$ emerges with parameters naturally in the MSW range. The nucleosynthesis constraint on the extra light particle species can be fulfilled by assuming the asymmetric postinflationary reheating between the usual and mirror worlds. One implication of our proposal is that bulk of the dark matter in the universe may be a warm dark matter consisting of the keV range mirror neutrinos rather than the conventional cold dark matter, while the mirror baryons can also contribute as dissipative dark matter. Implications of the mirror Machos for microlensing experiments are also discussed. [Talk given at the XIX int. conference on `Particle Physics and Astrophysics in the Standard Model and Beyond', Bystra, Poland, 19-26 September 1995 (to appear on Proceedings). Based on refs. \cite{BM,BDM} done in collaboration with A.D. Dolgov and R.N. Mohapatra]