Heterotic global anomalies and torsion Witten index

A bstract We study the structure of anomalies in general heterotic string theories by considering 2-dimensional $$ \mathcal{N} N = (0 , 1) supersymmetric quantum field (SQFTs), without assuming conformal invariance nor correct central charges. First we generalize precise notion B -field introduced Witten. Then express target space invariants SQFTs. Perturbative correspond to Witten index some class SQFTs, while global a torsion version index. The gives SQFTs suggested topological modular forms, and is expected be zero for cases that are relevant actual theories.