We propose a new dynamics of the electroweak symmetry breaking in a classically scale invariant version of the standard model. The scale invariance is broken by the condensations of additional fermions under a strong coupling dynamics. The electroweak symmetry breaking is triggered by negative mass squared of the elementary Higgs doublet, which is dynamically generated through the bosonic seesaw mechanism. We introduce a real pseudo-scalar singlet field interacting with additional fermions and Higgs doublet in order to avoid massless Nambu-Goldstone bosons from the chiral symmetry breaking in a strong coupling sector. We investigate the mass spectra and decay rates of these pseudo-Nambu-Goldstone bosons, and show they can decay fast enough without cosmological problems. We further show that our model can make the electroweak vacuum stable.
Haba, N., Ishida, H., Kitazawa, N., & Yamaguchi, Y. (2016). A new dynamics of electroweak symmetry breaking with classically scale invariance. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 755, 439–443. https://doi.org/10.1016/j.physletb.2016.02.052