Heterotic Calabi-Yau compactification
= Heterotic Calabi-Yau compactification
Compactification of a heterotic string on a <Calabi-Yau threefold> with a consistent <holomorphic vector bundle>. Suitable bundle and geometry choices preserve four-dimensional N=1 <supersymmetry> and generate chiral matter from internal Dirac zero modes. The index controls net chirality. In the standard embedding, the net generation index is half the internal <Euler characteristic>, up to chirality orientation conventions.