Two Higgs Pair Heterotic Vacua and Flavor-Changing Neutral Currents

Understand

We present a vacuum of heterotic M-theory whose observable sector has the MSSM spectrum with the addition of one extra pair of Higgs-Higgs conjugate superfields.

• The quarks/leptons have a realistic mass hierarchy with a naturally light first family.
• The double elliptic structure of the Calabi-Yau compactification threefold leads to two ``stringy'' selection rules.
• These classically disallow Yukawa couplings to the second Higgs pair and, hence, Higgs mediated flavor-changing neutral currents.