Connecting Electroweak Symmetry Breaking and Flavor: A Light Dilaton D and a Sequential Heavy Quark Doublet Q

Abstract

Abstract:The 125 GeV boson is quite consistent with the Higgs boson of the Standard Model (SM), but there is a challenge from Anderson as to whether this particle is in the Lagrangian. As Large Hadron Collider (LHC) Run 2 enters its final year of running, we ought to reflect and make sure we have gotten everything right. The ATLAS and CMS combined Run 1 analysis claimed a measurement of 5.4σ vector boson fusion (VBF) production which is consistent with SM, which seemingly refutes Anderson. However, to verify the source of electroweak symmetry breaking (EWSB), we caution that VBF measurement is too important for us to be imprudent in any way, and gluon-gluon fusion (ggF) with similar tag jets must be simultaneous measured, which should be achievable in LHC Run 2. The point is to truly test the dilaton possibility-the pseudo-Goldstone boson of scale invariance violation. We illustrate EWSB by dynamical mass generation of a sequential quark doublet (Q) via its ultrastrong Yukawa coupling and argue how this might be consistent with a 125 GeV dilaton, D. The ultraheavy 2m Q Á 4-5 TeV scale explains the absence of New Physics so far, while the mass generation mechanism shields us from the UV theory for the strong Yukawa coupling. Collider and flavor physics implications are briefly touched upon. Current Run 2 analyses show correlations between the ggF and VBF measurements, but the newly observed ttH production at LHC poses a challenge.Keywords: electroweak symmetry breaking; dilaton; sequential heavy quark doublet PACS: 11.15.Ex; 12.15.Ff; 14.65.Jk; 14.80.´j Higgs, Anderson, and All ThatSpontaneous symmetry breaking (SSB) was introduced into particle physics by Nambu as cross-fertilization from superconductivity (SC). In an explicit model with Jona-Lasinio (NJL), Nambu illustrated [1] how the nucleon mass m N could arise from dynamical chiral symmetry breaking (DχSB), with the pion emerging as a pseudo-Nambu-Goldstone (NG) boson. Subsequent work lead to the Brout-Englert-Higgs (BEH) mechanism [2,3] of electroweak symmetry breaking (EWSB), which became [4,5] part of the Standard Model (SM). The recently discovered 125 GeV boson [6,7] seems consistent with the Higgs boson of SM on every count. This has, in turn, stimulated condensed matter physicists to pursue their own "Higgs" mode.A "Higgs" mode was recently observed [8] in disordered SC films near the SC-insulator quantum critical point, far below the 2∆ double-gap threshold. Here, ∆ is the "energy gap" of the SC phase which is maintained throughout the experiment. This "light Higgs" mode contrasts with "amplitude modes" around 2∆ that were claimed long ago [9]. Anderson, who originated the nonrelativistic version of the BEH mechanism, praised [10] Nambu for elucidating [1] the dynamical generation of m N , a "mass gap", by drawing analogy with SC: a scalar boson in NJL-type of models with mass " 2m N is an