Tuesday, August 9, 2011

Introduction and Brief History of Particle Physics

There is a really great article over at Physics Today written by Steven Weinberg on particle physics entitled Particle physics, from Rutherford to the LHC. 

From the article:
It is clearly necessary to go beyond the standard model. There is a mysterious spectrum of quark and lepton masses and mixing angles that we have been staring at for decades, as if they were symbols in an unknown language, without our being able to interpret them. Also, something beyond the standard model is needed to account for cosmological dark matter. 
It is now widely understood that the standard model is just an effective field theory (see the box above), the low-energy limit of some more fundamental theory involving a scale of mass much larger than the masses with which we are familiar. That means we should expect the standard model to be supplemented with interactions that are not renormalizable in the usual sense—in fact, with all interactions allowed by symmetry principles—but suppressed by denominators proportional to powers of the large new mass. Infinities are still absorbed in a redefinition of the constants of the theory, but the number of constants that need to be redefined is no longer finite.
 The box he is talking about is here:
There is a great layman's introduction to effective field theories - which I find very interesting and did part of my dissertation on.


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