ar X iv : a st ro - p h / 01 04 25 1 v 1 1 5 A pr 2 00 1 Do mirror planets exist in our solar system ?

Mirror matter is predicted to exist if parity is an unbroken symmetry of nature. Currently, there is a large amount of evidence that mirror matter actually exists coming from astrophysics and particle physics. One of the most fascinating (but speculative) possibilities is that there is a significant abundance of mirror matter within our solar system. If the mirror matter condensed to form a large body of planatary or stellar mass then there could be interesting observable effects. Indeed studies of long period comets suggest the existence of a solar companion which has escaped direct detection and is therefore a candidate for a mirror body. Nemesis, hypothetical " death star " companion of the Sun, proposed to explain biological mass extinctions, may potentially be a mirror star. We examine the prospects for detecting these objects if they do indeed exist and are made of mirror matter. One of the most interesting candidates for dark matter coming from particle physics is " mirror matter ". Mirror matter is predicted to exist if parity is a symmetry of Nature (Lee and Yang 1956, Kobzarev et al. 1966, Pavšič 1974, Foot et al. 1991). The idea is that for each ordinary particle, such as the photon, electron, proton and neutron, there is a corresponding mirror particle, of exactly the same mass as the ordinary particle. The fundamental interactions of the mirror particles precisely mirrors those of the ordinary particles. For example, the mirror proton interacts with the mirror photon in precisely the same way in which an ordinary proton interacts with an ordinary photon. The mirror particles are not produced in laboratory experiments just because they couple very weakly to the ordinary particles. In the modern language of gauge theories, the mirror particles are all singlets under the standard G ≡ SU (3) ⊗ SU (2) L ⊗ U (1) Y gauge interactions. Instead the mirror particles interact with a set of mirror gauge particles, so that the gauge symmetry of the theory is doubled, i.e. G ⊗ G (the ordinary particles are, of course, singlets under the mirror gauge symmetry) (Foot et al. 1991). Parity is conserved because the mirror particles experience V + A mirror weak interactions and the ordinary particles experience the usual V − A weak interactions. Ordinary and mirror particles interact with each other predominately by gravity only. – 2 – While mirror matter has always been extremely well …