2012/06/26 by Mimura, Yukihiro, Hou, Wei-Shu, Kohyama, Hiroaki
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.1206.6063
A Higgs-like new boson with mass around 126 GeV is now established, but its true nature probably cannot be settled with 2011--2012 LHC data. We assume it is a dilaton with couplings weaker than the Higgs boson (except to γγ and gg), and explore dynamical symmetry breaking (DSB) by strong Yukawa coupling of a yet unseen heavy chiral quark doublet Q. Assuming the actual Higgs boson to be heavy, the Goldstone boson G of electroweak symmetry breaking still couples to Q with Yukawa coupling λQ. A ``bootstrap" gap equation without a Higgs particle is constructed. Electroweak symmetry breaking via strong λQ generates both heavy mass for Q, while self-consistently justifying G as a massless Goldstone particle in the loop. The spontaneous breaking of scale invariance in principle allows for a dilaton. We numerically solve such a gap equation and find the mass of the heavy quark to be a couple of TeV. We offer a short critique on the results of the scale-invariant model of Hung and Xiong, where a similar gap equation is built with a massless scalar doublet. Through this we show that a light SM Higgs at 126 GeV cannot be viable within our approach to DSB, while a dilaton with weaker couplings is consistent with our main result.