Realistic Yukawa Textures and SUSY Spectra from Intersecting Branes

TL;DR

This paper explores a string theory-based model with intersecting D-branes that naturally unifies gauge couplings, predicts low-energy supersymmetric spectra, and can reproduce realistic fermion masses and mixings, including neutrinos.

Contribution

It constructs a semi-realistic Pati-Salam model from intersecting D6-branes with automatic gauge unification and detailed low-energy phenomenology predictions.

Findings

Gauge coupling unification at the string scale.

Predicted Higgs mass below 120 GeV.

Dark matter density consistent with observations.

Abstract

We study the possible phenomenology of a three-family Pati-Salam model constructed from intersecting D6-branes in Type IIA string theory on the T^6/(Z2 x Z2) orientifold with some desirable semi-realistic features. In the model, tree-level gauge coupling unification is achieved automatically at the string scale, and the gauge symmetry may be broken to the Standard Model (SM) close to the string scale. The small number of extra chiral exotic states in the model may be decoupled via the Higgs mechanism and strong dynamics. We calculate the possible supersymmetry breaking soft terms and the corresponding low-energy supersymmetric particle spectra which may potentially be tested at the Large Hadron Collider (LHC). We find that for the viable regions of the parameter space the lightest CP-even Higgs boson mass usually satisfies m_H < 120 GeV, and the observed dark matter density may be generated. Finally, we find that it is possible to obtain correct SM quark masses and mixings, and the tau lepton mass at the unification scale. Additionally, neutrino masses and mixings may be generated via the seesaw mechanism. Mechanisms to stabilize the open and closed-string moduli, which are necessary for the model to be truly viable and to make definite predictions are discussed.