My question is (and it's probably stupid, I'm a layman, please have patience with me): It seems from what I've read that the Higgs boson, if it exists, is very unlikely to have an extremely high mass (above ~500 GeV), and probably has a mass under ~145 GeV. And I know the top quark with a mass of 170 GeV has been produced and detected at Tevatron, 15 years ago. So what is the crucial difference between the Higgs boson and the top quark, that the (presumably lighter) former hasn't been detected and the latter has? I understand some possible issues (it's easier to look for a particle if you can 'tune' your machines to its mass, but the mass of the top quark was unknown too, wasn't it? and you need considerably more energy than the mass of the particle since you will frequently lose energy in forming 'mundane' particles, but isn't this true for any particle, and presumably less so for a less massive one?) but I don't understand what the crucial difference is, why the 14 TeV LHC is needed to look for a 145 GeV particle when the Tevatron was sufficient to find the top quark.