In this paper we study several issues related to the generation of superpotential induced by background Ramond-Ramond fluxes in compactification of Type IIA string theory on Calabi-Yau four-folds. Identifying BPS solitons with D-branes wrapped over calibrated submanifolds in a Calabi-Yau space, we propose a general formula for the superpotential and justify it comparing the supersymmetry condit...

Superfield methods can be used to determine the precise way the self-dual fiveform couples to the metric in the first non-trivial α′ corrections to type IIB supergravity. We explicitly compute the exact tensor structure of these terms. This requires extensive use of computing algorithms to reduce the complicated expressions that appear to a surprisingly simple form. Along the way we show a new ...

We study T-duality in the Green-Schwarz formalism to all orders in superspace coordinates. We find two analogs of Buscher rules for the supervielbein and clarify their meaning from the superstring point of view. The transformation rules for the dilaton, spin 1/2 fermions and Ramond-Ramond superfields are also derived. E-mail: [email protected] E-mail: [email protected]

We derive the four dimensional N = 1/2 super Yang-Mills theory from tree-level computations in RNS open string theory with insertions of closed string Ramond-Ramond vertices. We also study instanton configurations in this gauge theory and their ADHM moduli space, using systems of D3 and D(–1) branes in a R-R background.

We utilize the integrality conjecture to show that torus partition function of a fermionic rational conformal theory in Ramond-Ramond sector becomes constant when bound ${h}^{R}\ensuremath{\ge}\frac{c}{24}$ is satisfied, where ${h}^{R}$ denotes weights Ramond states and $c$ central charge. The constant-valued strongly suggests presence supersymmetry unless given has free fermions. lower can the...