Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

N=1 Locally Supersymmetric Standard Models from Intersecting Branes

Christos Kokorelis

TL;DR

This work constructs four-dimensional intersecting D6-brane models on toroidal orientifolds that localize the MSSM spectrum with a shared $N=1$ supersymmetry. It develops four-, five-, and six-stack brane configurations, and demonstrates a RR homology flow connecting these vacua via brane recombination, while analyzing how complex-structure moduli, FI terms, and NS $B$-field influence SUSY breaking, Yukawa couplings, and gauge couplings. The study shows how low string scales can address the hierarchy and explores gauge-mediated SUSY breaking scenarios, highlighting the role of a non-factorizable brane in cancelling RR tadpoles and shaping the sparticle spectrum. The gauge coupling relations, moduli-dependent unification possibilities, and Yukawa textures are discussed across the model classes, with implications for neutrino masses and proton stability. Overall, the paper provides a framework for achieving MSSM-like physics in string theory through locally supersymmetric intersecting brane constructions and BR dynamics, with distinctive predictions for low-scale unification and SUSY breaking.

Abstract

We construct four dimensional intersecting D6-brane models that have locally the spectrum of the N=1 Supersymmetric Standard Model. All open {\em visible} string sectors share the same N=1 supersymmetry. As expected in these supersymmetric classes of models, where the D6-branes wrap a toroidal orientifold of type IIA, the hierarchy may be stabilized if the string scale is low, e.g. below 30 TeV. We analyze the breaking of supersymmetry in the vicinity of the supersymmetric point by turning on complex structure deformations as Fayet-Iliopoulos terms. Positive masses for all squarks and sleptons, to avoid charge/colour breaking minima, may be reached when also two loop contributions may be included. In the ultimate version of the present models N=1 supersymmetry may be broken by gauge mediation. The constructions with four, five and six stacks of D6-branes at $M_s$ are build directly. Next by the use of brane recombination we are able to show that there is a continuous, RR homology flow, between six, five and four stack models. Moreover, we examine the gauge coupling constants of the Standard Model $SU(3)_C$, $SU(2)_L$, $U(1)_Y$ at the string scale in the presence of a non-zero antisymmetric NS B-field.

N=1 Locally Supersymmetric Standard Models from Intersecting Branes

TL;DR

This work constructs four-dimensional intersecting D6-brane models on toroidal orientifolds that localize the MSSM spectrum with a shared supersymmetry. It develops four-, five-, and six-stack brane configurations, and demonstrates a RR homology flow connecting these vacua via brane recombination, while analyzing how complex-structure moduli, FI terms, and NS -field influence SUSY breaking, Yukawa couplings, and gauge couplings. The study shows how low string scales can address the hierarchy and explores gauge-mediated SUSY breaking scenarios, highlighting the role of a non-factorizable brane in cancelling RR tadpoles and shaping the sparticle spectrum. The gauge coupling relations, moduli-dependent unification possibilities, and Yukawa textures are discussed across the model classes, with implications for neutrino masses and proton stability. Overall, the paper provides a framework for achieving MSSM-like physics in string theory through locally supersymmetric intersecting brane constructions and BR dynamics, with distinctive predictions for low-scale unification and SUSY breaking.

Abstract

We construct four dimensional intersecting D6-brane models that have locally the spectrum of the N=1 Supersymmetric Standard Model. All open {\em visible} string sectors share the same N=1 supersymmetry. As expected in these supersymmetric classes of models, where the D6-branes wrap a toroidal orientifold of type IIA, the hierarchy may be stabilized if the string scale is low, e.g. below 30 TeV. We analyze the breaking of supersymmetry in the vicinity of the supersymmetric point by turning on complex structure deformations as Fayet-Iliopoulos terms. Positive masses for all squarks and sleptons, to avoid charge/colour breaking minima, may be reached when also two loop contributions may be included. In the ultimate version of the present models N=1 supersymmetry may be broken by gauge mediation. The constructions with four, five and six stacks of D6-branes at are build directly. Next by the use of brane recombination we are able to show that there is a continuous, RR homology flow, between six, five and four stack models. Moreover, we examine the gauge coupling constants of the Standard Model , , at the string scale in the presence of a non-zero antisymmetric NS B-field.

Paper Structure

This paper contains 15 sections, 64 equations, 3 figures, 18 tables.

Table of Contents

  1. Introduction
  2. N=1 local SYSY models revisited - Model I
  3. N=1 local SM vacua from five stacks of Intersecting D6-branes - Model II
  4. Supersymmetric Standard Model II
  5. Gauge Group Enhancement
  6. The N=1 Standard Model from Six-stacks of Intersecting D6-branes - Model III
  7. Yukawa Couplings
  8. Supersymmetry breaking and sparticle masses
  9. Brane recombination
  10. $Six \ stack \ BR SM's$
  11. $Five \ stack \ SM's$
  12. Gauge coupling constants
  13. Gauge mediated N=1 SUSY breaking
  14. Conclusions
  15. Appendix A

Figures (3)

  • Figure 1: Gauge group enhancement (and vice-versa) in the five stack quiver to a Pati-Salam $SU(4) \times SU(2)_L \times SU(2)_R \times U(1)^d$. The brane d on the left is shown to different positions.
  • Figure 2: Brane recombination, homology, flow between six, five and four stack quivers. Each quiver localizes the spectrum of N=1 Supersymmetric Standard Model. The solid lines between the nodes correspond to non-trivial intersections. The dotted lines correspond to parallel D6-branes.
  • Figure 3: One loop contributions to gaugino masses from heavy states, belonging to the NF brane, running in the loop. The possible supersymmetries respected by the NF brane are shown.