The Importance of Stability in Supersymmetry

In order for a particle to be a dark matter candidate, it has to be stable. So when we say a particle is stable, what we mean is that it never decays. If LEP had just had a little bit more energy, like 10% more than it had, it could have discovered the Higgs boson more than 10 years before the Large Hadron collider did. But of course, we didn't know that. We didn't know how heavy the Higgs was going to be. And we had to wait for the Large Hadril collider to make that discovery.