20 May 2005 | Kaustubh Agashe, Roberto Contino, Alex Pomarol
The paper presents a minimal composite Higgs model based on a five-dimensional (5D) AdS theory, where the Higgs is a pseudo-Goldstone boson (PGB) arising from a strongly interacting sector. The model incorporates electroweak symmetry breaking (EWSB) dynamically via top loop effects, solves all flavor problems, and ensures contributions to electroweak precision observables (EWPT) are within experimental bounds. The 5D theory is weakly coupled, allowing precise determination of the Higgs potential and other physical quantities. The lightest resonances are expected to have a mass around 2 TeV and should be discovered at the LHC. The top sector is mostly composite, with deviations from Standard Model (SM) couplings expected.
The model is based on a global SO(5)×U(1)_{B-L} symmetry, which includes the electroweak gauge group and provides an unbroken SO(3) custodial symmetry. The Higgs vacuum expectation value (VEV) is given by v = εf_π, where ε is a model-dependent parameter. The model can accommodate values of S and T consistent with EWPT for ε ≲ 0.4, achievable through mild tuning in the parameters. The Higgs is always very light, with m_Higgs ≲ 140 GeV, a key prediction of the model. Introducing an extra source of SO(5) breaking can increase the Higgs mass, while the model predicts extra gauge and fermionic resonances with masses ~1–3 TeV.
The model is described in two parts: a 4D model based on symmetry principles and a 5D AdS theory that leads to the same effective Lagrangian. The 5D theory is weakly coupled, allowing precise calculation of form factors, the S parameter, and the Higgs potential. The model predicts a Higgs mass around 115 GeV with ε ≲ 0.4, and the lightest resonances are expected to be around 2 TeV. The model also predicts a small correction to Z → b_L b_L and a T parameter that can be controlled for ε ≲ 0.4. The model is realistic and passes all EWPT, with the Higgs mass being light and the top mass being naturally small. The model is compared to other popular schemes of EWSB based on a PGB Higgs.The paper presents a minimal composite Higgs model based on a five-dimensional (5D) AdS theory, where the Higgs is a pseudo-Goldstone boson (PGB) arising from a strongly interacting sector. The model incorporates electroweak symmetry breaking (EWSB) dynamically via top loop effects, solves all flavor problems, and ensures contributions to electroweak precision observables (EWPT) are within experimental bounds. The 5D theory is weakly coupled, allowing precise determination of the Higgs potential and other physical quantities. The lightest resonances are expected to have a mass around 2 TeV and should be discovered at the LHC. The top sector is mostly composite, with deviations from Standard Model (SM) couplings expected.
The model is based on a global SO(5)×U(1)_{B-L} symmetry, which includes the electroweak gauge group and provides an unbroken SO(3) custodial symmetry. The Higgs vacuum expectation value (VEV) is given by v = εf_π, where ε is a model-dependent parameter. The model can accommodate values of S and T consistent with EWPT for ε ≲ 0.4, achievable through mild tuning in the parameters. The Higgs is always very light, with m_Higgs ≲ 140 GeV, a key prediction of the model. Introducing an extra source of SO(5) breaking can increase the Higgs mass, while the model predicts extra gauge and fermionic resonances with masses ~1–3 TeV.
The model is described in two parts: a 4D model based on symmetry principles and a 5D AdS theory that leads to the same effective Lagrangian. The 5D theory is weakly coupled, allowing precise calculation of form factors, the S parameter, and the Higgs potential. The model predicts a Higgs mass around 115 GeV with ε ≲ 0.4, and the lightest resonances are expected to be around 2 TeV. The model also predicts a small correction to Z → b_L b_L and a T parameter that can be controlled for ε ≲ 0.4. The model is realistic and passes all EWPT, with the Higgs mass being light and the top mass being naturally small. The model is compared to other popular schemes of EWSB based on a PGB Higgs.