### Abstract

We demonstrate the existence of heterotic string vacua that are free of massless exotic fields. The need to break the non-Abelian GUT symmetries in k = 1 heterotic string models by Wilson lines, while preserving the GUT embedding of the weak hypercharge and the GUT prediction sin^{2} θ_{w} (M_{GUT}) = 3 / 8, necessarily implies that the models contain states with fractional electric charge. Such states are severely restricted by observations, and must be confined or sufficiently massive and diluted. We construct the first quasi-realistic heterotic string models in which the exotic states do not appear in the massless spectrum, and only exist, as they must, in the massive spectrum. The SO (10) GUT symmetry is broken to the Pati-Salam subgroup. Our PS heterotic string models contain adequate Higgs representations to break the GUT and electroweak symmetry, as well as colour Higgs triplets that can be used for the missing partner mechanism. By statistically sampling the space of Pati-Salam vacua we demonstrate the abundance of quasi-realistic three generation models that are completely free of massless exotics, rendering it plausible that obtaining realistic Yukawa couplings may be possible in this space of models.

Original language | English |
---|---|

Pages (from-to) | 306-313 |

Number of pages | 8 |

Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |

Volume | 683 |

Issue number | 4-5 |

DOIs | |

Publication status | Published - 25 Jan 2010 |

Externally published | Yes |

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*Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics*,

*683*(4-5), 306-313. https://doi.org/10.1016/j.physletb.2009.12.033

}

*Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics*, vol. 683, no. 4-5, pp. 306-313. https://doi.org/10.1016/j.physletb.2009.12.033

**Exophobic quasi-realistic heterotic string vacua.** / Assel, Benjamin; Christodoulides, Kyriakos; Faraggi, Alon E.; Kounnas, Costas; Rizos, John.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Exophobic quasi-realistic heterotic string vacua

AU - Assel, Benjamin

AU - Christodoulides, Kyriakos

AU - Faraggi, Alon E.

AU - Kounnas, Costas

AU - Rizos, John

PY - 2010/1/25

Y1 - 2010/1/25

N2 - We demonstrate the existence of heterotic string vacua that are free of massless exotic fields. The need to break the non-Abelian GUT symmetries in k = 1 heterotic string models by Wilson lines, while preserving the GUT embedding of the weak hypercharge and the GUT prediction sin2 θw (MGUT) = 3 / 8, necessarily implies that the models contain states with fractional electric charge. Such states are severely restricted by observations, and must be confined or sufficiently massive and diluted. We construct the first quasi-realistic heterotic string models in which the exotic states do not appear in the massless spectrum, and only exist, as they must, in the massive spectrum. The SO (10) GUT symmetry is broken to the Pati-Salam subgroup. Our PS heterotic string models contain adequate Higgs representations to break the GUT and electroweak symmetry, as well as colour Higgs triplets that can be used for the missing partner mechanism. By statistically sampling the space of Pati-Salam vacua we demonstrate the abundance of quasi-realistic three generation models that are completely free of massless exotics, rendering it plausible that obtaining realistic Yukawa couplings may be possible in this space of models.

AB - We demonstrate the existence of heterotic string vacua that are free of massless exotic fields. The need to break the non-Abelian GUT symmetries in k = 1 heterotic string models by Wilson lines, while preserving the GUT embedding of the weak hypercharge and the GUT prediction sin2 θw (MGUT) = 3 / 8, necessarily implies that the models contain states with fractional electric charge. Such states are severely restricted by observations, and must be confined or sufficiently massive and diluted. We construct the first quasi-realistic heterotic string models in which the exotic states do not appear in the massless spectrum, and only exist, as they must, in the massive spectrum. The SO (10) GUT symmetry is broken to the Pati-Salam subgroup. Our PS heterotic string models contain adequate Higgs representations to break the GUT and electroweak symmetry, as well as colour Higgs triplets that can be used for the missing partner mechanism. By statistically sampling the space of Pati-Salam vacua we demonstrate the abundance of quasi-realistic three generation models that are completely free of massless exotics, rendering it plausible that obtaining realistic Yukawa couplings may be possible in this space of models.

UR - http://www.scopus.com/inward/record.url?scp=74049085470&partnerID=8YFLogxK

UR - https://www.journals.elsevier.com/physics-letters-b

U2 - 10.1016/j.physletb.2009.12.033

DO - 10.1016/j.physletb.2009.12.033

M3 - Article

VL - 683

SP - 306

EP - 313

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

SN - 0370-2693

IS - 4-5

ER -