  Redefining the vacuum state of a free two-fold $N=1$ covariant supersymmetric
string action as the one with all the excited states of world-sheet fermions
occupied, makes the theory anomaly free in (3+1)+4 dimensions. While in the
$NS$ sector the spectrum resembles the same for the standard $N=1$ superstring
theory with one of the $N$ species in the background, in the $R$ sector both
the species of fermions are required to describe the relevant spin operators to
describe the fermion spectra. A crucial difference from the $D=10, N=1$ theory
is that the fermions states are Dirac particles instead of Majorana-Weyl. Even
though the full spectrum of the theory contains both bosons and fermions of
various spin, there is no space-time supersymmetry due to obvious lack of
triality. The four coordinates of the 4 dimensional Euclidean space describes a
$CP^2$ to define the confined gauge symmetry $SU(3)_C$. The bosonization of
their supersymmetric partners yields additional two coordinates to describe a
$S^2$ that defines the $SU(2)_L$ of the Standard Model. There should be three
types of left-handed neutrinos. The right-handed neutrino becomes sterile.
Spinors and gauge bosons derive their masses through coupling to the tachyons
present in the spectrum via SSB and strings become point-particles below the
critical temperature.
