New ideas are being bandied about regarding the Higgs particle, which is expected possibly to be the signature discovery of the Large Hadron Collider in Europe. As I discussed in a 2007 posting, the Higgs is theorized to serve as a differentially permeable screen that gives different masses to various kinds of particles.
According to a blog at Discover magazine, findings from Fermilab's Tevatron collider have led some scientists to speculate that there may actually be five varieties of Higgs particle, instead of just one. Just to be clear, though, no discovery of a Higgs has yet been made. Quoting from the Discover blog:
Given, that the Fermilab found this [recent] result, we might wonder if they too will find these fascinating, elusive Higgs boson particles, perhaps stepping on the toes of their higher-energy rival, the Large Hadron Collider.