Sean Carroll had some great posts about the recent Higgs boson announcement. In particular the video he posted is quite moving, especially when Peter Higgs is shown saying he did not expect it in his lifetime. The enthusiasm is contagious.
But one point he made while liveblogging the event was not widely discussed since it would be a bummer:
Preliminary thought #1: There is a “nightmare scenario” that particle physicists have worried about for years. Namely: find exactly the Standard Model Higgs and nothing else at the LHC. I personally assign the nightmare scenario very low probability.
Note how Carroll personally thinks this is highly unlikely. But along those same lines, the NY Times quotes Maria Spiropulu “I personally do not want it to be standard model anything — I don’t want it to be simple or symmetric or as predicted. I want us all to have been dealt a complex hand that will send me (and all of us) in a (good) loop for a long time.”
To explain what they’re talking about, consider an analogy using Einstein’s general relativity. It predicts that starlight passing by the Sun will be slightly deflected. Newtonian physics also predicts bending, but relativity predicts twice as much. So it was possible that the bending would match Newtonian physics, it would match Einsteinian physics, or it would be something unexpected. As it turned out general relativity made the right prediction and that was that. In some sense this is analogous to the “nightmare scenario” above. The theory predicted something (the Higgs boson), the experiment matched the theory, and then…..we’re done. Back to the analogy, the anomalous result for relativity would have been three times bending which could have driven new theory. That’s what Sean Carroll is expecting and hoping for with the Higgs. Unexpected results. But in the nightmare case there may be no other major discovery from the $10 billion dollar Large Hadron Collider (LHC) besides the mass of the vanilla Higgs whose existence was predicted nearly 50 years ago.
From a historical point of view, particle physics back in the news reminds me of when I worked at a cushy college student job cleaning giant capacitors in the college hydrogen fusion lab. The grad student in charge would turn on college radio (Elvis Costello – eventually I got on board; Style Council – not so much). And we’d spend hours cleaning the oil off plastic rolled up insulators used in the giant capacitors, in turned used to trigger a fusion reaction. Now the first joke everyone was told at that lab when they started was that clean fusion power was only 20 years away, just as it was the year before, and the year before that, and so on to this very day. The lab itself was a bit rundown since it was better funded in earlier days when the cold war made funding easier to come by.
Stephen Wolfram’s take seems to match my feelings: “If the Standard Model is correct, yesterday’s announcement is likely to be the last major discovery that could be made in a particle accelerator in our generation.” That’s someone else who expects the nightmare scenario. The heydey of particle physics is captured in this graphic from the Economist, where during the 1960’s and early 1970’s most of the Standard Model was put together. Note the clustering of discoveries and theories in the heydey era.
In Kuhnian terms the Higgs is “normal science”: working out the details of existing theory. Recently some of the most unexpected observations are coming from astronomy – dark matter, dark energy.
Most particle physicist hope they’ll now find something unexpected about the Higgs behavior so this can further drive theory. That would be great if it happens. But if it does not happen, the next decade will be hard on particle physicists. History will view this as the final coda to that 1960-1970 era. And at some point undoubtedly people will question the $10 billion LHC price tag. For example, would we get more science out of things like the $788 million Euclid telescope hunting for dark matter and dark energy. I guess I wouldn’t be surprised if that were the case. But I think the right attitude about the Higgs is that until the question of its existience was put to bed, we just couldn’t know. That’s just how science works. You have to try stuff out, and even if it closes the door in one direction, that just makes it more clear where to go next. We should defend the LHC now on the basis of the vanilla Higgs alone, not in the hope that future experiments will necessarily break a lot of new ground. The nightmare scenario is still good science.