Supersymmetric technicolor

We propose a supersymmetric model of particle physics in which supersymmetry is broken dynamically by strong gauge forces. The model, as it stands, requires that one parameter be fine tuned; a grand unified version would not require any fine tuning. The model has no strong CP problem, and agrees with all known particle physics experiments. A variety of new particles, many of which weigh less than 100 GeV, are predicted.     

Superconformal technicolor

In supersymmetric theories with a strong conformal sector, soft supersymmetry breaking at the TeV scale naturally gives rise to confinement and chiral symmetry breaking at the same scale. We consider two such scenarios, one where the strong dynamics induces vacuum expectation values for elementary Higgs fields, and another where the strong dynamics is solely responsible for electroweak symmetry breaking. In both cases, the mass of the Higgs boson can exceed the LEP bound without tuning, solving the supersymmetry naturalness problem. A good precision electroweak fit can be obtained, and quark and lepton masses are generated without flavor-changing neutral currents. In addition to standard supersymmetry signals, these models predict production of multiple heavy standard model particles (t, W, Z, and b) from decays of resonances in the strong sector.     

Minimal supersymmetric technicolor

We introduce novel extensions of the Standard Model featuring a supersymmetric technicolor sector. First we consider N=4\mathcal{N}=4 Super Yang–Mills which breaks to N=1\mathcal{N}=1 via the electroweak (EW) interactions and coupling to the MSSM. This is a well defined, economical and calculable extension of the SM involving the smallest number of fields. It constitutes an explicit example of a natural supersymmetric conformal extension of the Standard Model featuring a well defined connection to string theory. It allows us to interpolate, depending on how we break the underlying supersymmetry, between unparticle physics and Minimal Walking Technicolor. As a second alternative we consider other N = 1\mathcal{N} =1 extensions of the Minimal Walking Technicolor model. The new models allow all the standard model matter fields to acquire a mass.     

More supersymmetric technicolor

We propose a supersymmetric model of particle physics in which supersymmetry is broken by strong gauge forces. Unlike previous realistic supersymmetric technicolor theories, the model contains only one extra strong gauge group, and it lends itself readily to grand unification. The model also has no light axions which can burn out stars. A variety of new particles, many weighing less than 100 GeV, are predicted. A no-go theorem due to Witten is discussed.     

Model of vectorlike technicolor

The authors consider the mechanism of formation of techniquark states which have a vectorlike interaction with the standard bosons. It is shown that the simplest variant of the vectorlike technicolor does not contradict to the new physics restrictions. It is suggested that the technibaryon scalar states are regarded as dark matter candidates.     

A walk with technicolor

We propose an ETC model based on SO(10)² which naturally accomodates a complete family of technifermions in the 7 of SO(7)_TC plus three generations of quarks and leptons. The technicolor sector corresponds to one of the examples recently shown by Appelquist et al. to avoid the flavor-changing neutral-current problem. In order to obtain an interesting fermion mass spectrum we propose a composite version of the ETC model based on SO(10)³.     

Search for technicolor with DELPHI

Technicolor represents a viable alternative to the Higgs mechanism for generating gauge boson masses. Searches for technicolor particles and have been performed in the data collected by the DELPHI experiment at LEP at centre-of-mass energies between 192 and 208 GeV corresponding to an integrated luminosity of 452 pb. Good agreement is observed with the SM expectation in all channels studied. This is translated into an excluded region in the plane. The production is excluded for all GeV/c. Assuming a point-like interaction of the with gauge bosons, an absolute lower limit on the charged mass at 95% CL is set at 79.8 GeV/c, independently of other parameters of the technicolor model. Received: 10 August 2001 / Published online: 5 November 2001     

Minimal technicolor on the lattice

We present results from a lattice study of SU(2) gauge theory with 2 flavors of Dirac fermions in adjoint representation. This is a candidate for a minimal (simplest) walking technicolor theory, and has been predicted to possess either an IR fixed point (where the physics becomes conformal) or a coupling which evolves very slowly, so-called walking coupling. In this initial part of the study we investigate the lattice phase diagram and the excitation spectrum of the theory.     

Holographic technicolor model and dark matter

We investigate the strongly coupled minimal walking technicolor model (MWT) in the framework of a bottom-up holographic model, where the global \begin{document}$ SU(4)$\end{document} symmetry breaks into \begin{document}$ SO(4)$\end{document} subgroups. In the holographic model, we found that 125 GeV composite Higgs particles and small Peskin–Takeuchi S parameter can be achieved simultaneously. In addition, the model predicts a large number of particles at the TeV scale, including dark matter candidates Technicolor Interacting Massive Particles (TIMPs). If we consider the dark matter nuclear spin-independent cross-section in the range of \begin{document}$ 10^{-45}\sim 10 ^ {-48} \;{\rm{cm}}^2$\end{document}, which can be detected by future experiments, the mass range of TIMPs predicted by the holographic technicolor model is \begin{document}$ 2 \sim 4$\end{document} TeV.     

Negative S parameter from holographic technicolor

We present a new class of 5D models, Holographic Technicolor, which fulfills the basic requirements for a candidate of comprehensible 4D strong dynamics at the electroweak scale. It is the first Technicolor-like model able to provide a vanishing or even negative tree-level S parameter, avoiding any no-go theorem on its sign. The model is described in the large-N regime. S is therefore computable: possible corrections coming from boundary terms follow the 1/N suppression, and generation of fermion masses and the S parameter issue do split up. We investigate the model's 4D dual, probably walking Technicolor-like with a large anomalous dimension.     

A light scalar in low-scale technicolor

In addition to the narrow spin-one resonances ρT${\rho }_T$, ωT${\omega }_T$ and aT$a_T$ occurring in low-scale technicolor, there will be relatively narrow scalars in the mass range 200 to 600–700 GeV. We study the lightest isoscalar state, σT${\sigma }_T$. In several important respects it is like a heavy Higgs boson with a small vev. It may be discoverable with high luminosity at the LHC where it is produced via weak boson fusion and likely has substantial W⁺W⁻$W^{+}{W}^{-}$ and Z⁰Z⁰$Z^0{Z}^0$ decay modes.