The Intermediate Higgs
Emanuel Katz, Ann E. Nelson, Devin G. E. Walker
TL;DR
The paper introduces the Intermediate Higgs framework, a non-supersymmetric approach to electroweak symmetry breaking in which the Higgs is a pseudo-Nambu-Goldstone boson. By employing collective symmetry breaking, the one-loop quadratic sensitivity from the top quark is canceled by heavy vector-like quarks, allowing a higher cutoff (up to ~6 TeV) while keeping precision electroweak corrections modest. It presents three concrete realizations based on coset structures SU(4)/Sp(4), SU(5)/SO(5), and SU(6)/Sp(6), each featuring new weak-scale scalars and multiple vector-like quarks, with vacuum alignment determining the Higgs properties and, in some cases, making the Higgs mass calculable. The work also discusses collider signatures, precision constraints, FCNC considerations, and possible UV completions (strong dynamics or extra-dimensional scenarios), highlighting distinctive phenomenology and testable predictions for upcoming experiments.
Abstract
Two paradigms for the origin of electroweak superconductivity are a weakly coupled scalar condensate, and a strongly coupled fermion condensate. The former suffers from a finetuning problem unless there are cancelations to radiative corrections, while the latter presents potential discrepancies with precision electroweak physics. Here we present a framework for electroweak symmetry breaking which interpolates between these two paradigms, and mitigates their faults. As in Little Higgs theories, the Higgs is a pseudo-Nambu Goldstone boson, potentially composite. The cutoff sensitivity of the one loop top quark contribution to the effective potential is canceled by contributions from additional vector-like quarks, and the cutoff can naturally be higher than in the minimal Standard Model. Unlike the Little Higgs models, the cutoff sensitivity from one loop gauge contributions is not canceled. However, such gauge contributions are naturally small as long as the cutoff is below 6 TeV. Precision electroweak corrections are suppressed relative to those of Technicolor or generic Little Higgs theories. In some versions of the intermediate scenario, the Higgs mass is computable in terms of the masses of these additional fermions and the Nambu-Goldstone Boson decay constant. In addition to the Higgs, new scalar and pseudoscalar particles are typically present at the weak scale.