yomamma said:
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
