Model Building and Naturalness

Over the last few months (and this will certainly continue over the next few years) I have been spending some time boning up on particle physics phenomenology and the associated model-building issues. Part of my research involves investigating the cosmological implications of such models, while at other times I am interested in how certain outstanding cosmological questions might be addressed by new particle physics beyond the standard model. These, plus the upcoming turn-on of the Large Hadron Collider (LHC), are some of the reasons that I have been spending time on phenomenology. I've been thinking about this particularly today after a nice seminar by Ian Low from the Institute for Advanced Study (IAS) in Princeton. The content of Ian's seminar isn't really what I want to discuss here, but part of what he spoke about got me thinking about a question I've wanted to get into for a while. Most ...