Related papers: A Fermionic Top Partner: Naturalness and the LHC
We perform an analysis of the electroweak precision observables in the Lee-Wick Standard Model. The most stringent restrictions come from the S and T parameters that receive important tree level and one loop contributions. In general the…
A model is presented in which O(10 TeV) stop masses, typically required by the Higgs boson mass in supersymmetric models, do not originate from soft supersymmetry breaking terms that would drive the Higgs mass squared parameter to large…
We present an update of the Standard Model fit to electroweak precision data. We include newest experimental results on the top quark mass, the W mass and width, and the Higgs boson mass bounds from LEP, Tevatron and the LHC. We also…
In composite Higgs models with partial compositeness, the small value of the observed Higgs mass implies the existence of light fermionic resonances, the top partners, whose quantum numbers are determined by the symmetry (and symmetry…
The discovery of a 125 GeV Higgs boson and rising lower bounds on the masses of superpartners have lead to concerns that supersymmetric models are now fine tuned. Large stop masses, required for a 125 GeV Higgs, feed into the electroweak…
The main challenge faced by Higgsless models of electroweak symmetry breaking is to reconcile the experimental constraints imposed by the precision electroweak data and the top quark phenomenology with the unitarity constraints imposed by…
The electroweak symmetry may be broken by a composite Higgs which arises naturally as a bound state of the top quark if the standard model gauge fields and fermions propagate in extra dimenions. The top quark mass and the Higgs mass can be…
We study methods of extracting new physics signals in final states with a top-quark pair plus large missing energy at the LHC. We consider two typical examples of such new physics: pair production of a fermionic top partner (a $T'$ in…
The discovery of a new boson with a mass of approximately 125 GeV in 2012 at the LHC has heralded a new era in understanding the nature of electroweak symmetry breaking and possibly completing the standard model of particle physics. Since…
The 2HDM possesses a neutral scalar interaction eigenstate whose tree-level properties coincide with the Standard Model (SM) Higgs boson. In light of the LHC Higgs data which suggests that the observed Higgs boson is SM-like, it follows…
We derive a phenomenological no-lose theorem for naturalness up to the TeV scale, which applies when quantum corrections to the Higgs mass from top quarks are canceled by perturbative BSM particles (top partners) of similar multiplicity due…
Composite Higgs models provide a natural, non-supersymmetric solution to the hierarchy problem. In these models, one or more sets of heavy top-partners are typically introduced. Some of these new quarks can be relatively light, with a mass…
Common lore has it that naturalness of electroweak breaking in the SM requires new physics (NP) at Lambda < 2-3 TeV, hopefully within the reach of LHC. Moreover the Higgs should be light (m_h < 219 GeV) to pass electroweak precision tests…
We compute the Coleman Weinberg effective potential for the Higgs field in RS Gauge-Higgs unification scenarios based on a bulk SO(5) x U(1)_X gauge symmetry, with gauge and fermion fields propagating in the bulk and a custodial symmetry…
We investigate the implications of the Higgs rate measurements from Run 1 of the LHC for the mass of the light scalar top partner (stop) in the Minimal Supersymmetric Standard Model (MSSM). We focus on light stop masses, and we decouple the…
The large top Yukawa coupling results in the top quark contributing significantly to the quantum correction of the Higgs mass term. Traditionally, this effect is canceled by the presence of top partners in symmetry-based models. However,…
The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing…
Electroweak symmetry breaking and the origin of mass of fermion and boson are fundamental questions to understand particle physics. The essential piece of this symmetry breaking, the Higgs boson, is the most probable particle to be…
We examine a model with multiple scalar fields to see whether it is possible to reduce the fine- tuning of the SM Higgs mass without introducing low scale top partners. Our approach may be regarded as a generalization of the condition…
Precision measurements of high energy top quarks at the LHC constitute a powerful probe of new physics. We study the effect of four fermion operators involving two tops and two light quarks on the high energy tail of the $t\bar t$ invariant…