How is broken symmetry really observed?

[Redsummers]

Hello,

Now that there's only one week left until the LHC starts working on the collisions, I think it's a good idea for me to ease my mind and ask how will they observe superparticles and discern them from the SM particles.

 

[bapowell]

Good question. There is no tag that each super particle will carry that says "I'm a result of supersymmetry breaking!". Rather, they will infer whether or not a new particle is a result of SUSY by its mass and spin. If they start discovering craploads of heavy scalars at LHC, that's a good sign that SUSY is an actual (broken) symmetry of nature. If the mass splittings between these scalars and the fermions of the SM align with current parameterizations of MSSM, even better. The bosons of the SM will also be expected to have heavier fermion partners.

However, let's say that at the end of the day LHC discovers one new heavy fermion. What does that mean? It of course could be SUSY, and that's probably what everyone would conclude because it's one of the only sensible extensions to the SM that predicts heavy fermions. But it would not be a smoking gun.

 

[Redsummers]

Oh sounds good! I get now the idea of what to expect to come out, for a success in LHC. Makes sense why they have to be a heavy scalars, otherwise they should've been observed previously. I must say that I am not really familiar with MSSM, so I will go ask my friend google, and if I have any further questions I may end up asking in this thread again.