Cross-posted from Scimatic
The Large Hadron Collider at CERN turned on last week to much fanfare. It managed to make Google’s front page image. Fortunately, they avoided this. It’s quite a technical achievement, decades in the making, and the LHC is the "undiscovered country" of experimental particle physics. However, I have mixed feelings about it.
My physics career, short as it was, always concentrated on small experiments. While at Fermilab, I didn’t work on either of the flagship experiments (CDF or DZero), which had about 500 physicists per experiment. My thesis experiment had about 80 people, which was of the scale that if you wanted to, you could learn how all the pieces worked. That’s not possible on the larger experiments — they’re just too big. And it seems that the smaller experiments are being pushed to the side as all of particle physics is consolidated into one single, massive experiment. We’re already at the point where the world can only support one accelerator, LHC, with two primary experiments — ATLAS and CMS. Eventually, all particle physicists will have to work on a single, ginormous experiment and I think something will be lost when that happens.
The science outcomes of the LHC are not in the bag, either. The closest thing to a slam-dunk is finding the Higgs boson, which is the gauge boson responsible for generating mass. The Standard Model predicts a Higgs boson in the range of the mass of the electroweak gauge bosons (the Ws and the Z), and therefore is in the range of the LHC. If the LHC doesn’t find it, we have some serious problems with the Standard Model. That would be really cool, as everything so far lines up perfectly with the Standard Model. A little break from that perfect streak would be nice. Even Stephen Hawking thinks so. The rest of the physics program could be anything. They might find super-symmetrical particles; they might not. Or they might find something else completely.
Should we be doing this? There’s the historical argument that "spin-out" from high energy physics will occur, and the prime example, as offered by an interviewee on CBC‘s "Quirks and Quarks", is the electron; that no one before the discovery of the electron would have imagined a world with electronics. So try to imagine what will be possible with all the amazing new science we will discover at the LHC! Problem is: it’s a false analogy. Electrons are stable, and are of an appropriate scale. By which I mean one can build transistors and integrated circuits and the typical wavelength of an electron is not a problem. However, there are no devices equivalent to electronics built out of any of the new particles we’ve discovered in the last 50 years, and I doubt there will be. With the possible exception of Data‘s positronic brain. And that’s because those particles aren’t stable.
Barring that, there’s always the discussion of ancillary benefits, like advances in computing and engineering. Problem with that is the spin seems to go the other way. When I was at Fermilab, the computing advances were "spin-in". We’d buy SGI computers second-hand from Hollywood. The beowulf cluster ideas came from NASA. The only spin-out that I saw was that the RF engineers could get better deals working for the cell companies.
Science needs lots of different competing ideas, or at least competing groups trying different ideas. Lee Smolin has highlighted the problem with theoretical particle physicists putting all their eggs in a string theory basket, and the experimentalists should be equally wary. And it’s possible that while they’re spending 10 years to build this thing, the excitement will shift to a different area. Lately it seems like all the cool stuff is dark matter and dark energy coming from astronomy/astrophysics and cosmology, where the budgets are way less than the bajillion dollars it cost to build the LHC. In a way, particle physics has become the Microsoft of science: big, monolithic, slow to change. The detectors even kind of look like a Borg ship.
So why do it? Well, one cynical physicist I knew said that the US funded high energy physics to keep a stable of educated scientists around in case they had to draft them at some point into a weapons program. I’m not sure about that, but it raises some tough questions. We are betting the physics farm on this, and I don’t feel consolidation into a homogenous landscape is right for the field. Maybe we need to get back to the ethic of one great hero of Canadian science: "We don’t have the money, so we have to think," and start really thinking about small and inventive experiments.
Like I said, mixed feelings.