Related papers: Gaugino Condensation in Heterotic Fivebrane Backgr…
We investigate, at the microscopic level, the compatibility between D-term potentials from world-volume fluxes on D7-branes and non-perturbative superpotentials arising from gaugino condensation on a different stack of D7-branes. This is…
The generic observable sector gaugino mass in the weakly-coupled heterotic string compactified to four dimensions by the Scherk-Schwarz scheme (together with hidden sector gaugino condensation inducing the super-Higgs effect with a…
We study the structure of soft breaking terms in the context of a gaugino condensation scenario. Assuming that the Supergravity Lagrangian is the correct quantum field theory limit, at some momentum scale $\mu_{UV}$, of a more fundamental…
Strongly coupled heterotic $E_8\times E_8$ string theory, compactified to four dimensions on a large Calabi-Yau manifold ${\bf X}$, may represent a viable candidate for the description of low-energy particle phenomenology. In this regime,…
Supersymmetry breaking may be linked to the formation of gaugino condensates in a hidden sector. In this work, the process of formation of the condensate is examined in a cosmological context, using an effective field theory of the gaugino…
We discuss the propagation of gravity in five-dimensional Minkowski space in the presence of a four-dimensional brane. We show that there exists a solution to the wave equation that leads to a propagator exhibiting four-dimensional behavior…
Within the ongoing debate about de Sitter (dS) vacua in string theory, different aspects of explicit dS proposals have come under intense scrutiny. One key ingredient is D7-brane gaugino condensation, which is usually treated using…
We consider hidden sector supersymmetry breakdown in the strongly coupled heterotic $E_8\times E_8$ theory of Ho\v{r}ava and Witten. Using effective field theory methods in four dimensions, we can show that gravitational interactions induce…
The Conformal Field Theory of the current algebra of the centrally extended 2-d Euclidean group is analyzed. Its representations can be written in terms of four free fields (without background charge) with signature ($-$+++). We construct…
The propagator of a scalar field on a stationary slowly varying in space gravitational background is derived retaining only the second derivatives of the metric. The corresponding one-loop effective action is constructed. The propagator and…
We consider supersymmetric theories where the standard-model quark and lepton fields are localized on a "3-brane" in extra dimensions, while the gauge and Higgs fields propagate in the bulk. If supersymmetry is broken on another 3-brane,…
We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a…
The explicit form of the fermionic zero-modes in the fivebrane backgrounds of type IIA and IIB supergravity theories is investigated. In type IIA fivebrane background there are four zero-modes of gravitinos and dilatinos. In type IIB…
We present remarkably simple covariant expressions for the graviton and ghost propagators in Anti-de Sitter and de-Sitter spacetimes valid in any spacetime dimension. In gravity there is a $2$-parameter family of covariant gauge-fixing…
We discuss non-perturbative aspects of string effective field theories with N=1 supersymmetry in four dimensions. By the use of a scalar potential, which is on-shell invariant under the supersymmetric duality of the dilaton, we study…
The existence of de Sitter solutions in string theory is strongly constrained by no-go theorems. We continue our investigation of corrections to the heterotic effective action, with the aim of either strengthening or evading the these…
The exchange of a pair of neutrinos with Standard Model weak interactions generates a long-range force between fermions. The associated potential is extremely feeble, $\propto G_F^2/r^5$ for massless neutrinos, whichrenders it far from…
Alternative gauge choices for worldsheet supersymmetry can elucidate dynamical phenomena obscured in the usual superconformal gauge. In the particular example of the tachyonic $E_8$ heterotic string, we use a judicious gauge choice to show…
We derive the explicit form, and discuss some properties of the moduli dependent effective potential arising from M-theory compactified on $M_4 \times X\times S^1 / Z_2 $, when one of the boundaries supports a strongly interacting gauge…
We have systematically constructed the general structure of the gauge boson self-energy and the effective propagator in presence of a nontrivial background like hot magnetized material medium. Based on this as well as the general structure…