Electroweak Symmetry Breaking and Extra Dimensions

TL;DR

This paper explores models where electroweak symmetry breaking occurs through extra-dimensional configurations of known particles, avoiding new fundamental fields below the quantum gravitational scale, and successfully reproduces the top-quark mass.

Contribution

It proposes a novel scheme where the QCD gauge group in extra dimensions forms a composite Higgs, aligning with the Standard Model without introducing new fundamental particles below 10-100 TeV.

Findings

The effective low-energy theory matches the Standard Model.

The top-quark mass is consistent with experimental data.

Electroweak symmetry breaking is achieved without new fundamental fields.

Abstract

Electroweak symmetry can be naturally broken by observed quark and gauge fields in various extra-dimensional configurations. No new {\it fundamental} fields are required below the quantum gravitational scale ($\sim$ 10 - 100 TeV). We examine schemes in which the QCD gauge group alone, in compact extra dimensions, forms a composite Higgs doublet out of (t,b)_L and a linear combination of the Kaluza-Klein modes of t_R. The effective theory at low energies is the Standard Model. The top-quark mass is controlled by the number of active t_R Kaluza-Klein modes below the string scale, and is in agreement with experiment.