By now I have forgotten most of the details of the talk, so below is a sketch of the small amount of notes that I took.
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The first part was to mention that the LHC will explore the weak energy scale. This energy scale is around 1 TeV. The weak scale is many orders above the Planck scale and many orders bellow the Hubble scale. This is part of the so-call Hierarchy problem.
This large leap make an "unnatural" fine tuning to 1 in 10^(-120) figures (in what I think is the cosmological constant, but I clearly suck at taking notes). Nima also mentioned that if you put a bunch of theoretical physicist in a spaceship, they will probably discover the Standard Model, with the right physics but all the numbers wrong.
An experimentalist fine-tunes a metal for example. (But I forgot the analogy here... :-( ).
Naturalness = compute until things blow in your face. For the weak scale to be natural, there should be some cutoff at 1 TeV. The LHC will run with 14 TeV in center of mass energy.
Nima then goes on to tell the story of the classical electron and the observation of the positron. Composite objects generate a doubling in degrees of freedom. For the weak scale there are two broad ideas:
- Supersymmetry (SUSY) - Bosons related to fermions, couplings related. This phenomena should show up at the TeV scale.
- Composites (Higgs made of techniquarks) - New dynamics.
An example of fine tuning is the nearly perfect alignment of the sun and the moon during an eclipse. The moon is the right size to cover the sun perfectly and leave a white halo.
The acceleration of the universe would be another finely-tuned aspect of the universe. If this were not the case, no structures would have ever formed. God? Other mechanism? Our planet is where structure is, around nebulae.
He then went on to talk about other universes, and looking for them. He also commented on split supersymmetry, but at this point I was already day dreaming. :-[
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