  Recently a class of Type IIA orientifold models was constructed yielding just
the fermions of the SM at the intersections of D6-branes wrapping a 6-torus. We
generalize that construction to the case of Type IIB compactified on an
orientifold of T^4 \times (C/Z_N) with D5-branes intersecting at angles on T^4.
We construct explicit models in which the massless fermion spectrum is just the
one of a three-generation Standard Model.
  One of the motivations for these new constructions is that in this case there
are 2 dimensions which are transverse to the SM D5-brane configuration. By
making those two dimensions large enough one can have a low string scale M_s of
order 1-10 TeV and still have a large M_{Planck} in agreement with
observations. From this point of view, these are the first explicit D-brane
string constructions where one can achieve having just the fermionic spectrum
and gauge group of the SM embedded in a Low String Scale scenario. The
cancellation of U(1) anomalies turns out to be quite analogous to the toroidal
D6-brane case and the proton is automatically stable due to the gauging of
baryon number. Unlike the D6-brane case, the present class of models has N = 0
SUSY both in the bulk and on the branes and hence the spectrum is simpler.

High Energy Physics - Theory;High Energy Physics - Phenomenology