What is technicolor as an alternative to the Higgs boson?

Question

What is technicolor as an alternative to the Higgs boson?

Answer 1

The Higgs field, mediated by the Higgs boson, is proposed as an explanation of why the weak interaction is so much weaker than electromagnetism; the Higgs field interacts with the weak vector bosons W+, W-, and Z0 and not with the photon, giving the weak vector bosons mass. This lowers the coupling constant (Fermi constant) because it requires more energy to produce these particles.

Technicolor is intended to solve a different problem, the hierarchy problem. Note that at a high energy, the weak and electromagnetic interactions actually become equal in strength. However, we prefer to look at it the other way around: the two forces are fundamentally alike, and become different in strength when the energy falls below a certain value. This is called spontaneous symmetry breaking. This phenomenon is caused by a field, hence the Higgs field and Higgs boson theory.

Spontaneous symmetry breaking is interesting. Current predictions are: Above the Planck energy which is about 10^32 eV, all particles are massless and the four forces have equal strengths. Below 10^32 eV, gravity weakens while the strong-electroweak combined force strengthens; When the energy is lowered to around 10^30 eV, the strong force splits off from the electroweak force, becoming stronger as the electroweak force becomes weaker; around 10^11 to 10^12 eV (100-1000 GeV), the electroweak force splits into the electromagnetic force, which strengthens as the energy is further lowered; and the weak force, which weakens as the energy is further lowered. At this point also, the particles of the Standard Model acquire their masses.

Interestingly enough, lowering the energy even further eventually produces a Bose-Einstein condensate or a fermionic condensate; a quantum-mechanical state of matter in which all particles are in their ground states. Superfluid helium-4 below the lambda transition point is an example of a Bose-Einstein condensate, whereas superfluid helium-3 is a fermionic condensate.

The question is, however, why are these energies so different? Why should we expect that the energy at which the strong force is differentiated, is so much higher than the energy at which the weak and electromagnetic forces are differentiated? We could postulate additional fields, hence, a particle 10^20 times more massive than the Higgs could be responsible for the strong-electroweak breaking, for example. However, this doesn't solve the problem itself, because the mass of this particle would have to be a fundamental parameter of the equations, and the question we set out to answer is why some constants in the model should differ from others so much. Technicolor is another proposed explanation, one in which there is no Higgs boson (so yes, you could call it an alternative.)

The page on Wikipedia is complicated, but here is an excerpt from the book Dreams of a Final Theory by Steven Weinberg:

"A version of the standard model that is based ont he introduction of new extra-strong (technicolor) forces would avoid the hierarchy problem because there would be no masses at all in the equations that describe physics at energies far below the Planck energy. The scale of masses of the W and Z particles and the other elementary particles of the standard model would be related instead to the way that the strength of the technicolor force changes with energy. The technicolor force as well as the strong and electroweak forces would be expected to have the same intrinsic strength at some very high energy, not very different from the Planck energy. With decreasing energy its strength would increase very slowly, so that the technicolor force would not become strong enough to break any symmetries until the energy drops to a value very much lower than the Planck energy. It is quite plausible that without any fine-tuning of the constants of the theory the technicolor force would strengthen with decreasing energy a little faster than the ordinary color [strong] force, so that it could give something like the observed masses for the W and Z particles of the standard model, while the ordinary color force acting alone would give them masses a thousand times smaller." (p. 311-312)

Make of this what you will, for I don't understand it completely myself.