Dark Energy and Dark Matter, Mirror World and E₆ Unification

In the present talk we have developed a concept of parallel ordinary (O) and mirror (M) worlds. We have shown that in the case of a broken mirror parity (MP), the evolutions of fine structure constants in the O- and M-worlds are not identical. It is assumed that E_6-unification inspired by superstring theory restores the broken MP at the scale \sim 10^{18} GeV, what unavoidably leads to the different E_6-breakdowns at this scale: E_6 \to SO(10)\times U(1)_Z - in the O-world, and E'_6 \to SU(6)'\times SU(2)'_Z - in the M-world. Considering only asymptotically free theories, we have presented the running of all the inverse gauge constants \alpha_i^{-1} in the one-loop approximation. Then a `quintessence' scenario is discussed for the model of accelerating universe. Such a scenario is related with an axion (`acceleron') of a new gauge group SU(2)'_Z which has a coupling constant g_Z extremely growing at the scale \Lambda_Z\sim 10^{-3} eV.