What is the significance of the Higgs Boson in particle physics?

[JamesU]

I'm wondering about the higgs boson, or "god particle". If it is said that it turned energy into matter, that has to be false, because it is matter itself.

 

[JamesU]

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[Mk]

Don't do that.

It's mass is right at the maximum energy they could run the [LEP] at. But the indirect indications are that the Higgs boson should be close to that value.
-Brian Webber, professor of theoretical physics at Cambridge

I don't think it turns energy into matter, I think it gives matter mass.

The higgs boson is one of the particles on the line between matter and not. Like the photon. There's two kinds of mass, photons have one, Higgs bosons have only one, the same as the photon. The Higgs bson is the particle that ends up insuring that matter as we know it, have both types of mass.

We hope when the LHC gets running between 2006-2007, the Higgs will be found soon. At approximately 1 TeV, 1000 GeV It's almost 10 times more energetic than the LEP.

Table of basic particles:
http://newsimg.bbc.co.uk/media/images/39882000/gif/_39882466_standard_model2_416.gif

 

[marlon]

I'm wondering about the higgs boson, or "god particle". If it is said that it turned energy into matter, that has to be false, because it is matter itself.

The Higgs mechanism gives mass to elementary particles via symmetry breaking in the physical groundstate. This state does not have the same symmetry properties as the Lagrangian of the actual system, hence symmetry is broken.

If you want to give mass to elementary particles you cannot just write a m-term in the L because certain symmetries will automatically be broken. This is not good because these symmetries need to be respected in order for the Lagrangian to be a GOOD Lagrangian that describes the physical theory correctly.

The solution is this, don't write m but write down scalar field (of which the excitations are the Higgs-bosons, and being scalar also explains why there is no Higgs fermion), that was subject to a funny potential such that in the ground state (lowest energy) the field values would NOT be 0.

Indeed, the non-zero value of that field, coupled with an interaction term between that field and, say, the electron field, gave a term in the lagrangian which DID respect the symmetries required, but mimicked, at low energies, as a term that was essentially the same as a mass term.


It also solved another problem: there were 2 theorems in quantum field theory that made life hard. The first one was by 't Hooft, and said that if you want to have a renormalizable (calculable) theory, your interactions need to be described by fields such that the lagrangian obeys, what is called, a gauge symmetry. The problem with a gauge symmetry was that gauge particles have to be massless. People tried to find tricks around it, but Goldstone proved an annoying theorem (Goldstone's theorem), that said that you always have to have massless particles associated with the degrees of freedom of a gauge symmetry, the socalled "goldstone bosons". As these were not observed, that was annoying.
And then the Higgs mechanism was invented. It gave terms that mimicked mass to the gauge particles, it eliminated the goldstone bosons and gave, by its interactions, a mimicked mass term to the fermions.


regards
marlon