### Abstract

We compute the leading corrections to the properties of W and Z bosons induced at the one-loop level in the SU(5)/SO(5) Littlest Higgs model with T parity, and perform a global fit to precision electroweak data to determine the constraints on the model parameters. We find that a large part of the model parameter space is consistent with data. Values of the symmetry breaking scale f as low as 500 GeV are allowed, indicating that no significant fine tuning in the Higgs potential is required. We identify a region within the allowed parameter space in which the lightest T-odd particle, the partner of the hypercharge gauge boson, has the correct relic abundance to play the role of dark matter. In addition, we find that a consistent fit to data can be obtained for large values of the Higgs mass, up to 800 GeV, due to the possibility of a partial cancellation between the contributions to the T parameter from Higgs loops and new physics.

Original language | English (US) |
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Pages (from-to) | 3441-3464 |

Number of pages | 24 |

Journal | Journal of High Energy Physics |

Issue number | 1 |

DOIs | |

State | Published - 2006 |

Externally published | Yes |

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### Keywords

- Beyond Standard Model
- Higgs Physics
- LEP HERA and SLC Physics
- Technicolor and Composite Models

### ASJC Scopus subject areas

- Nuclear and High Energy Physics

### Cite this

*Journal of High Energy Physics*, (1), 3441-3464. https://doi.org/10.1088/1126-6708/2006/01/135