Exact Standard Model structures from intersecting D5-branes

Abstract

We discuss the appearance of non-supersymmetric compactifications with exactly the Standard Model (SM) at low energies, in the context of IIB orientifold constructions with D5 branes intersecting at angles on the T 4 tori, of the orientifold of T 4 × (C/Z N ). We discuss constructions where the Standard Model embedding is considering within four, five and six stacks of D5 branes. The appearance of the three generation observable Standard Model at low energies is accompanied by a gauged baryon number, thus ensuring automatic proton stability. Also, a compatibility with a low scale of order TeV is ensured by having a two dimensional space transverse to all branes. The present models complete the discussion of some recently constructed four stack models of D5 branes with the SM at low energy. By embedding the four, five and six stack Standard Model configurations into quiver diagrams, deforming them around the QCD intersection numbers, we find a rich variety of vacua that may have exactly the Standard Model at low energy. Also by using brane recombination on the U(1)'s, we show that the five and six vacua flow into their four stack counterparts. Thus string vacua with five and six stack deformations are continuously connected to the four stack vacua.

Noncommutative Black Holes, the Final Appeal to Quantum Gravity: A Review

“…This hypothesis is currently considered to be the unique viable solution to the long-standing hierarchy problem, namely the presence of two fundamental scales in nature, the electroweak scale and the Planck scale, separated by 16 orders of magnitude [70][71][72][73][74][75][76][77][78][79] . The main point in this potential resolution of the problem is that extra dimensions can be assumed to be as large as around a millimeter, if we suppose that Standard Model fields are constrained in a four dimensional sub-manifold of the higher dimensional spacetime, and that only gravity can probe the additional transverse dimensions.…”

Stability of Lovelock black holes under tensor perturbations

“…Apparently, it is necessary to reconcile this prediction with our real world by compactifying extra-dimensions or by considering braneworld. Recently, the idea of large extra-dimensions in the context of the braneworld has been advocated [1,2,3]. Intriguingly, in the presence of the large extra-dimensions, black holes could be created at the TeV scale [4].…”

On the Casimir Effect for Parallel Plates in the Spacetime With One Extra Compactified Dimension

“…Some branches of string theory expect that the radii of the compactified universal extra dimensions should be Planck size which is beyond our experimental reach of today and near future [3,4]. In some approaches large extra dimensions were also invoked for providing a breakthrough of hierarchy problem [5][6][7][8][9][10]. The gauge fields may be localized on a four-dimensional brane, our real universe, and only gravitons can propagate in the extra space transverse to the brane [8,9].…”