  A mirror-extended standard model (MESM) is offered, where in the left-right
symmetric underlying action the sector of the standard model (SM) and its
mirror copy have the same SU(2)\times U(1) gauge structure and parameters; the
mirror fermion counter-partners have opposite chiralities. A theory is used
that allows one to obtain MESM in Minkowski space only if we start with an
accurate account of gravity and only at the end go to the limit of Minkowski
space. Spontaneous breaking of left-right symmetry and the "wrong" sign in the
mass terms of the Higgs fields potentials arise due to the initial conditions
imposed on the T-model inflation. MESM allows choosing the universal Yukawa
coupling constant $y$ in the underlying Lagrangian for all generations of
charged leptons and up-quarks. As an example, with y=10^{-3}, it is shown that
a set of additional dimensionless parameters in width range less than 0.5 is
sufficient to obtain the masses of all known charged leptons and up-quarks. In
this sense, MESM bypasses the problem of the fermion mass hierarchy. With this
choice of parameters, MESM predicts that vacuum expectation value for the
mirror Higgs field is 10^{14}GeV and masses of mirror particles are in the
range 10^{8}GeV-10^{14}GeV. There is only gravitational interaction between
particles of the SM and mirror sectors. Hence, mirror particles can constitute
dark matter. The vacuum is realized as a limiting state in the cosmological
evolution of the inflaton and classical Higgs fields, in which the energy
stored in them becomes minimal, providing the maximum possible contribution of
these fields to the entropy of the Universe. If further study of the model
reveals the existence of an effective mechanism for preheating the Universe,
this will mean that the cosmological constant problem is absent.
