Zoom virtual journal club: https://cern.zoom.us/j/697426096
Non-perturbative superpotential contributions of Heterotic worldsheet instantons depend on the Kahler, complex structure, and bundle moduli of the underlying string compactification. It has been observed in the context of non-linear sigma models that these contributions can show a surprising cancelation among different curves within the same curve class. We will analyze this cancelation from an algebraic point of view for monad or extension bundles over complete intersection Calabi-Yau manifolds. We discuss how to identify the curves in a given curve class, compute the contributing Pfaffians and their moduli dependence, and study the aforementioned cancelation for these classes of models. We also discuss their gauged linear sigma model realization.