  We consider string phenomenological models based on 11D Horava-Witten
M-theory with 5 branes in the bulk. If the 5-branes cluster close to the
distant orbifold plane (d_n\equiv 1-z_n\simeq 0.1) and if the topological
charges of the physical plane vanish (\beta^{(0)}_i=0), then the Witten
\epsilon terms (to first order) are correctly small and a qualitative picture
of the quark and lepton mass hierarchy arises without significant fine tuning.
If right handed neutrinos exist, a possible gravitationally induced cubic
holomorphic contribution to the Kahler potential can exist scaled by the 11D
Planck mass. These terms give rise to Dirac neutrino masses at the electroweak
scale. This mechanism (different from the see-saw mechanism) is seen to account
for both the atmospheric and solar neutrino oscillations. The model also gives
rise to possible non-universal soft breaking A parameters in the u and d second
and third generation quark sector (A_{2,3}^{(u,d)}) which naturally can account
for the possible (2.4\sigma) break down of the Standard Model predictions in
the recent B-factory data for the B->\phi K_s decays.
