Collider Cross Talk

Chiral-symmetric strongly coupled sectors at the LHC

by Roman Pasechnik (Lund University)

Thursday, 11 April 2013 from to (Europe/Zurich)
at CERN ( 4-2-011 - TH common room )
Most of the traditional Technicolor-based models are known to be in a strong tension with the electroweak precision data. We show that this serious issue is naturally cured in strongly coupled sectors with chiral-symmetric gauge interactions. We discuss possible phenomenological implications of such non-standard chiral-symmetric Technicolor scenario in its simplest formulation preserving the standard Higgs mechanism and elementary Higgs boson of the Standard Model (SM). For this purpose, we assume the existence of an extra technifermion sector confined under extra SU(3)_TC at the energy scales reachable at the LHC, Lambda_TC ~ 0.1-1 TeV, and interacting with the SM gauge bosons in a chiral-symmetric way. In the framework of this scenario, the SM Higgs vev acquires natural interpretation in terms of the condensate of chiral technifermions in confinement. We study the influence of the lowest lying composite physical states, namely, technipions, technisigma and constituent technifermions, on the Higgs sector properties in the SM and some possible effects on other observables at the LHC. We found out that the Higgs signal in gamma gamma, vector-boson VV* and fermion, e.g. b bbar, decay channels can be rather sensitive to this new sector if Lambda_TC is not very far from the electroweak scale. In particular, the effects of technisigma-Higgs boson mixing and extra technifermion loops can affect the Higgs boson branching ratios being currently studied at the LHC.