CERN - Large Hadron Collider and the Very Early Universe

A few things. The first and foremost is "What broke electroweak symmetry?" That is, what is the explicit mechanism where by our world settled into a state where the electroweak force appears as two separate forces. The most commonly used mechanism in our theories is the Higgs field, which basically provides a background against which the electromagnet force and the weak force appear separate. This is similar to how the presence of an atmosphere on earth can make momentum appear not to be conserved.However there are several other supposed mechanisms and the LHC will test them as well. Unfortunately the LHC has been misreported as a machine built to find the Higgs Boson, but that is not its aim. Finding the Higgs boson would mean that the simplest mechanism of electroweak symmetry breaking is the right one. However not finding it wouldn't be some kind of disaster.After that the next major thing would be detecting the presence of supersymmetry particles. Supersymmetry is basically the biggest symmetry a quantum field theory can have and its existence would imply new particles.After that it may be capable of telling us if there is extra dimensions or put limits on how large extra dimensions can be. Several versions of supersymmetry, certain mechanisms of electroweak symmetry breaking and theories with large extra dimensions. The discovery of supersymmetry particles would indicate string theory is on the right track. As for the origin of the universe, the LHC may tell us what material makes up Dark Matter, which is important for cosmology and theories of the early universe. That wouldn't be its direct or expected contribution. Rather it will improve our understanding of particle theory, which may then be used to aid the study of cosmology.

The one major difference between the end of the last century and now is that our current theories are too general for the previous centuries problem solving methods to work. For instance, instead of being able to come up with just any theory there are several strong arguments that no matter what is actually going on, physics at low energies like ours can be described by a quantum field theory. One is constrained by the results of quantum theory and relativity to use quantum field theory. So regardless of what's behind the symmetry breaking, it'll almost certainly still be described by a quantum field theory.In Cosmology, the unanswered questions are more likely to be solved from some unexpected observation. However again we face a different dilemma compared with the previous centuries. In previous centuries existing models had catastrophic failures when applied to the problematic phenomena in question. However this time round we have several models which have no problem describing the phenomena, but no current way of choosing between them. The only reason the LHC is so "powerful" is because you need that much energy to access the energy scale where electroweak symmetry breaking occurs. Unfortunately it's unlikely that you could discover anything about symmetry breaking unless you can access those energies.

There are convincing theoretical reasons to think the Higgs particle will not be found. The Weinberg-Salam-Glashow model of the electroweak interaction gives predictions which are perfectly in agreement with experiment. However the model supposes that electroweak force is seperates in the weak and electromagentic force in a certain way so as to obtain the results which match experiment.We know from studies of the early universe that the electroweak force did seperate, however the specific mechanism by which this occured is not known. Several mechanisms were proposed with the Higgs being the simplest. However obviously another method could be correct. For any proposed method there are arguments for or against it, the Higgs has the most arguments in its favour and it's the easiest calculationally.Edited by Son Goku, : Small edit