Compactified String Theories - Generic Predictions for Particle Physics

yanniru

A review paper by Bobby Samir Acharya, Gordon Kane and Piyush Kumar
http://arxiv.org/pdf/1204.2795v1.pdf 12 April 2012

This is my first post here in a long time.
I learned of this paper from yesterday's Lubos Motl blog.
It is the most instructive string theory paper I have ever read.

But I have a questions.
AKK derive two low energy effective supergravity theories:
one for M-theory and another for F-theory IIb.

Their conclusion is that the M-effective theory contains
"a metric, a 3-form gauge field (C) and a gravitino" at low energies along with:

"a perturbative superpotential for the moduli [that]vanishes exactly.
This is a key point which distinguishes M theory on a G2-manifold from other compactifications such as Type IIB and heterotic string theories on a Calabi-Yau manifold. For instance, Calabi-Yau manifolds generically have complex structure moduli; since these moduli are already complex fields, the corresponding supermultiplets do not have a shift symmetry and, consequently, the superpotential can contain perturbative contributions dependent on these fields." excerpt from AKK paper.

My question is if a vanishing perturbative superpotential implies a true vacuum whereas a field-dependent perturbative superpotential implies a false vacuum?

The paper is impressive in that it predicts Dark Matter axions distributed logarithmically over a 10^-33 to 1 eV mass range and predicts that Dark Matter WIMPs will exist only if gauginos are suppressed.
Richard Ruquist