A ug 1 99 9 Mirror World versus large extra dimensions

Recently proposed low scale quantum gravity scenario is expected to have a significant impact on the Mirror World hypothesis. Some aspects of this influence is investigated here, assuming that the fundamental gravity scale is near a TeV. It is shown that future colliders will be capable to produce the mirror matter, but an experimental signature, which will distinguish such events from the background, is unclear. The " smoking gun " signals of the Mirror World are Υ(2S) → ˜ Υ(1S)π + π − and Υ(2S) → ˜ Υ(1S)π 0 π 0 decays, expected at a level of 10 −9. Finally, it is shown that a mirror supernova will be quite a spectacular event for our world too, because a considerable amount of ordinary energy is expected to be emitted in the first several seconds.