Chiral supergravity actions and superforms

Understand

The superform construction of supergravity actions, christened the "ectoplasm method," is based on the use of a closed super d-form in the case of d space-time dimensions.

• In known examples, such superforms are obtained by iteratively solving nontrivial cohomological problems.
• The latter usually makes this scheme no less laborious than the normal coordinate method for deriving component actions for matter-coupled supergravity.
• In this note we present an alternative procedure to generate required superforms in four space-time dimensions, which makes use of self-dual vector multiplets.