Flux-lines through Calabi-Yau manifolds and related couplings

The mixed Yukawa couplings of the 27 and 27* superfields to other superfields are studied in a model stemming from a superstring model compactified on a generic Calabi-Yau manifold. The coupling to the standard E₆-algebra-valued flux-loop operator, as well as an analogous E₆-invariant operator, is argued to be related to certain Yukawa couplings. A vacuum expectation value of the latter operator is shown to give masses to all E₆-singlet scalar superfields, except for those stemming from the supergravity multiplet.