Related papers: A Novel Solution to the Gravitino Problem
We present a new 3-brane solution to Einstein's equations in (1+5)-spacetime with a negative bulk cosmological constant. This solution is a stringlike defect solution with decreasing scale function approaching a finite non-zero value in the…
Fundamental superstrings (F-strings) and D-strings may be produced at high temperature in the early Universe. Assuming that, we investigate if any of the instabilities present in systems of strings and branes can give rise to a…
We present a non-compact (4 + 1) dimensional model with a local strong four-fermion interaction supplementing it with gravity. In the strong coupling regime it reveals the spontaneous translational symmetry breaking which eventually leads…
As is well known, the gravitational degrees of freedom contained in $R+\zeta R^{2}$ (super)gravity lead to Starobinsky's potential, in a one-field setting for inflationary Cosmology that appears favored by Planck data. In this letter we…
In this paper we consider the gauge theory living on the world-volume of a stack of N D3-branes of Type 0B/\Omega' I_6(-1)^{F_{L}} and of its orbifolds C^2/Z_2 and C^3/(Z_2 x Z_2). The gauge theories obtained in the three cases are a brane…
We construct black string solutions in Type IIA supergravity arising from intersecting D2-D4-D6-NS5 branes in the presence of fractional D4-branes. The fractional D4-branes arise from D6-branes wrapping (collapsing) two-cycles in a…
We discuss possible variations of the effective gravitational constant with length scale, predicted by most of alternative theories of gravity and unified models of physical interactions. After a brief general exposition, we review in more…
In this work there are proposed several new 6D brane worlds based on exact topological solutions to the vortex equations for the Abelian Higgs model, with suitable boundary conditions and symmetry breaking potentials similar to the mexican…
The four-dimensional Minkowski space-time is considered as a three-brane embedded in five dimensions, using solutions of five-dimensional supergravity. These backgrounds have a string theoretical interpretation in terms of D3-brane…
This article discusses model-building scenarios including anti-D3-/D7-branes, in which supersymmetry is broken spontaneously, despite having no scale at which sparticles appear and standard supersymmetry is restored. If the branes are…
We point out that models where gauge and charged matter fields live on the world volume of D3 branes can provide a weak string coupling description of the gauge coupling unification in the supersymmetric standard model at a scale of order…
The world volume theory on $N$ regular and $M$ fractional D3-branes at the conifold singularity is a non-conformal ${\cal N}=1$ supersymmetric $SU(N+M)\times SU(N)$ gauge theory. In previous work the extremal Type IIB supergravity dual of…
We derive a low-energy effective theory for gravity with anti-D branes, which are essential to get de Sitter solutions in the type IIB string warped compactification, by taking account of gravitational backreactions of anti-D branes. In…
We study soft leptogenesis in gauge mediated supersymmetry breaking models with an enhanced A-term for the right-handed neutrino. We find that this scenario can explain the baryon asymmetry of the present universe, consistently with the…
We study models with contributions of similar size to the soft masses from anomaly- and gravity mediation, thereby curing the tachyonic slepton problem of anomaly mediation. A possible origin of this hybrid setup in a 5-dimensional brane…
This project explores the $D=11$ supergravity model and the properties of its p-brane ansatz. The initial field content (graviton, gravitino and the anti-symmetric tensor field) in the action of $D=11$ supergravity is explained in the…
We analyze the propagation of a scalar field in multidimensional theories which include kinetic corrections in the brane, as a prototype for gravitational interactions in a four dimensional brane located in a (nearly) flat extra dimensional…
We study geometries produced by brane intersections preserving eight supercharges. Typical examples of such configurations are given by fundamental strings ending on Dp branes and we construct gravity solutions describing such…
If the gravitino is sufficiently light and stable it will behave as an effective massless neutrino species at the time of nucleosynthesis. Depending on the temperature at which it decouples from the thermal bath in the early universe, the…
We address the issue of whether extra dimensions could have an infinite volume and yet reproduce the effects of observable four-dimensional gravity on a brane. There is no normalizable zero-mode graviton in this case, nevertheless correct…