A UV complete partially composite-pNGB Higgs

TL;DR

This paper proposes a UV-complete model combining a fundamental Higgs with a composite pNGB doublet, offering a natural electroweak symmetry breaking mechanism with distinctive phenomenological signatures and suppressed experimental constraints.

Contribution

It introduces a UV-complete, partially composite Higgs model based on SU(4)/Sp(4), with novel features like vacuum misalignment and specific resonance behaviors.

Findings

Hierarchy between $ m ilde{ ext{TC}}$ scale and electroweak scale depends on vacuum misalignment.

Lightest vector resonances are in 10-plet, 5-plet, and singlet of Sp(4).

Higgs coupling deviations are around 1%.

Abstract

We explore an electroweak symmetry breaking (EWSB) scenario based on the mixture of a fundamental Higgs doublet and an SU(4)/Sp(4) composite pseudo-Nambu-Goldstone doublet -- a particular manifestation of bosonic technicolor/induced EWSB. Taking the fundamental Higgs mass parameter to be positive, EWSB is triggered by the mixing of the doublets. This setup has several attractive features and phenomenological consequences, which we highlight: i) Unlike traditional bosonic technicolor models, the hierarchy between $\Lambda_{\rm TC}$ and the electroweak scale depends on vacuum (mis)alignment and can be sizable, yielding an attractive framework for natural EWSB; ii) As the strong sector is based on SU(4)/Sp(4), a fundamental (UV-complete) description of the strong sector is possible, that is informed by the lattice; iii) The lightest vector resonances occur in the 10-plet, 5-plet and singlet of Sp(4). Misalignment leads to a 10-plet "parity-doubling" cancelation in the $S$ parameter, and a suppressed 5-plet contribution; iv) Higgs coupling deviations are typically of $\mathcal O(1\%)$; v) The 10-plet isotriplet resonances decay dominantly to a massive technipion and a gauge boson, or to technipion pairs, rather than to gauge boson or fermion pairs; moreover, their couplings to fermions are small. Thus, the bounds on this setup from conventional heavy-vector-triplet searches are weak. A supersymmetric $U(1)_R$ symmetric realization is briefly described.