Non-supersymmetric heterotic model building

Understand

We investigate orbifold and smooth Calabi-Yau compactifications of the non-supersymmetric heterotic SO(16)xSO(16) string.

• We focus on such Calabi-Yau backgrounds in order to recycle commonly employed techniques, like index theorems and cohomology theory, to determine both the fermionic and bosonic 4D spectra.
• We argue that the N=0 theory never leads to tachyons on smooth Calabi-Yaus in the large volume approximation.
• As twisted tachyons may arise on certain singular orbifolds, we conjecture that such tachyonic states are lifted in the full blow-up.