Natural four-generation mass textures in MSSM brane worlds

Richard Lebed, Van E. Mayes

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A fourth generation of standard model fermions is usually considered unlikely due to constraints from direct searches, electroweak precision measurements, and perturbative unitarity. We show that fermion mass textures consistent with all constraints may be obtained naturally in a model with four generations constructed from intersecting D6-branes on a T6/(Z 2×Z2) orientifold. The Yukawa matrices of the model are rank 2, so that only the third- and fourth-generation fermions obtain masses at the trilinear level. The first two generations obtain masses via higher-order couplings and are therefore naturally lighter. In addition, we find that the third and fourth generations automatically split in mass, but do not mix at leading order. Furthermore, the standard model gauge couplings automatically unify at the string scale, and all the hidden-sector gauge groups become confining in the range 1013-1016GeV, so that the model becomes effectively a four-generation minimal supersymmetric standard model at low energies.

Original languageEnglish (US)
Article number105015
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume84
Issue number10
DOIs
StatePublished - Nov 11 2011

Fingerprint

textures
fermions
confining
sectors
strings
matrices
energy

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Natural four-generation mass textures in MSSM brane worlds. / Lebed, Richard; Mayes, Van E.

In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 84, No. 10, 105015, 11.11.2011.

Research output: Contribution to journalArticle

@article{7816c88c81264dd88927f61b928e9959,
title = "Natural four-generation mass textures in MSSM brane worlds",
abstract = "A fourth generation of standard model fermions is usually considered unlikely due to constraints from direct searches, electroweak precision measurements, and perturbative unitarity. We show that fermion mass textures consistent with all constraints may be obtained naturally in a model with four generations constructed from intersecting D6-branes on a T6/(Z 2×Z2) orientifold. The Yukawa matrices of the model are rank 2, so that only the third- and fourth-generation fermions obtain masses at the trilinear level. The first two generations obtain masses via higher-order couplings and are therefore naturally lighter. In addition, we find that the third and fourth generations automatically split in mass, but do not mix at leading order. Furthermore, the standard model gauge couplings automatically unify at the string scale, and all the hidden-sector gauge groups become confining in the range 1013-1016GeV, so that the model becomes effectively a four-generation minimal supersymmetric standard model at low energies.",
author = "Richard Lebed and Mayes, {Van E.}",
year = "2011",
month = "11",
day = "11",
doi = "10.1103/PhysRevD.84.105015",
language = "English (US)",
volume = "84",
journal = "Physical review D: Particles and fields",
issn = "1550-7998",
publisher = "American Institute of Physics Publising LLC",
number = "10",

}

TY - JOUR

T1 - Natural four-generation mass textures in MSSM brane worlds

AU - Lebed, Richard

AU - Mayes, Van E.

PY - 2011/11/11

Y1 - 2011/11/11

N2 - A fourth generation of standard model fermions is usually considered unlikely due to constraints from direct searches, electroweak precision measurements, and perturbative unitarity. We show that fermion mass textures consistent with all constraints may be obtained naturally in a model with four generations constructed from intersecting D6-branes on a T6/(Z 2×Z2) orientifold. The Yukawa matrices of the model are rank 2, so that only the third- and fourth-generation fermions obtain masses at the trilinear level. The first two generations obtain masses via higher-order couplings and are therefore naturally lighter. In addition, we find that the third and fourth generations automatically split in mass, but do not mix at leading order. Furthermore, the standard model gauge couplings automatically unify at the string scale, and all the hidden-sector gauge groups become confining in the range 1013-1016GeV, so that the model becomes effectively a four-generation minimal supersymmetric standard model at low energies.

AB - A fourth generation of standard model fermions is usually considered unlikely due to constraints from direct searches, electroweak precision measurements, and perturbative unitarity. We show that fermion mass textures consistent with all constraints may be obtained naturally in a model with four generations constructed from intersecting D6-branes on a T6/(Z 2×Z2) orientifold. The Yukawa matrices of the model are rank 2, so that only the third- and fourth-generation fermions obtain masses at the trilinear level. The first two generations obtain masses via higher-order couplings and are therefore naturally lighter. In addition, we find that the third and fourth generations automatically split in mass, but do not mix at leading order. Furthermore, the standard model gauge couplings automatically unify at the string scale, and all the hidden-sector gauge groups become confining in the range 1013-1016GeV, so that the model becomes effectively a four-generation minimal supersymmetric standard model at low energies.

UR - http://www.scopus.com/inward/record.url?scp=82955225357&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=82955225357&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.84.105015

DO - 10.1103/PhysRevD.84.105015

M3 - Article

AN - SCOPUS:82955225357

VL - 84

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 1550-7998

IS - 10

M1 - 105015

ER -