# Quartification on an orbifold

## Abstract

We investigate quartification models in five dimensions, with the fifth dimension forming an S{sup 1}/Z{sub 2}xZ{sub 2}{sup '} orbifold. The orbifold construction is combined with a boundary Higgs sector to break the quartified gauge group directly to a group H subset of SU(3){sup 4} which is operative at the electroweak scale. We consider H=G{sub SM}xSU(2){sub l} and H=G{sub SM}, where G{sub SM} is the standard model gauge group, and find that unification occurs only when the remnant leptonic color symmetry SU(2){sub l} remains unbroken. Furthermore, the demands of a realistic low-energy fermion spectrum specify a unique symmetry breaking route for the unifying case of H=G{sub SM}xSU(2){sub l}. We contrast this with four-dimensional quartification models where unification may be achieved via a number of different symmetry breaking routes both with and without the remnant SU(2){sub l} symmetry. The boundary Higgs sector of our model may be decoupled to achieve a Higgsless limit, and we show that the electroweak Higgs doublet may be identified as the fifth component of a higher-dimensional gauge field.

- Authors:

- School of Physics, Research Centre for High Energy Physics, University of Melbourne, Victoria 3010 (Australia)

- Publication Date:

- OSTI Identifier:
- 21020108

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevD.75.056006; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ENERGY SPECTRA; FERMIONS; FOUR-DIMENSIONAL CALCULATIONS; HIGGS BOSONS; HIGGS MODEL; MANY-DIMENSIONAL CALCULATIONS; STANDARD MODEL; SU-2 GROUPS; SU-3 GROUPS; SYMMETRY; SYMMETRY BREAKING

### Citation Formats

```
Demaria, Alison, and McDonald, Kristian L.
```*Quartification on an orbifold*. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVD.75.056006.

```
Demaria, Alison, & McDonald, Kristian L.
```*Quartification on an orbifold*. United States. doi:10.1103/PHYSREVD.75.056006.

```
Demaria, Alison, and McDonald, Kristian L. Thu .
"Quartification on an orbifold". United States.
doi:10.1103/PHYSREVD.75.056006.
```

```
@article{osti_21020108,
```

title = {Quartification on an orbifold},

author = {Demaria, Alison and McDonald, Kristian L.},

abstractNote = {We investigate quartification models in five dimensions, with the fifth dimension forming an S{sup 1}/Z{sub 2}xZ{sub 2}{sup '} orbifold. The orbifold construction is combined with a boundary Higgs sector to break the quartified gauge group directly to a group H subset of SU(3){sup 4} which is operative at the electroweak scale. We consider H=G{sub SM}xSU(2){sub l} and H=G{sub SM}, where G{sub SM} is the standard model gauge group, and find that unification occurs only when the remnant leptonic color symmetry SU(2){sub l} remains unbroken. Furthermore, the demands of a realistic low-energy fermion spectrum specify a unique symmetry breaking route for the unifying case of H=G{sub SM}xSU(2){sub l}. We contrast this with four-dimensional quartification models where unification may be achieved via a number of different symmetry breaking routes both with and without the remnant SU(2){sub l} symmetry. The boundary Higgs sector of our model may be decoupled to achieve a Higgsless limit, and we show that the electroweak Higgs doublet may be identified as the fifth component of a higher-dimensional gauge field.},

doi = {10.1103/PHYSREVD.75.056006},

journal = {Physical Review. D, Particles Fields},

number = 5,

volume = 75,

place = {United States},

year = {Thu Mar 01 00:00:00 EST 2007},

month = {Thu Mar 01 00:00:00 EST 2007}

}