Monday, July 09, 2012
Higgs 1, Neutrinos 0
The world of high-energy physics breathed a collective sigh of relief last Wednesday when a team of researchers at CERN, the European physics lab, announced results from their Large Hadron Collider (LHC) that make it “99 percent certain” there is indeed a thing called the Higgs boson. Further work is needed before the discovery makes it to the point that there’s only a one-in-a-million chance that it’s not true, which is allegedly the standard that physicists now maintain before a new particle is generally accepted. But judging by the signs of exultation and emotion, such as the tears of Peter Higgs (the theorist who first predicted the particle in the 1960s), such acceptance is only a matter of time.
The mood at CERN contrasts with the emotions that a much less publicized announcement last February probably inspired. Late last fall, some CERN researchers working with an Italian physics lab known (appropriately) as OPERA announced that they had clocked a subatomic particle called a neutrino (Italian for “little neutron”) as going just a hair faster than light. I blogged on this last October 9 and remarked that if it turned out to be false, you wouldn’t see any headlines about it. Well, I was wrong, but the headlines were a lot smaller than the ones about the discovery of the Higgs boson.
Turns out that the OPERA people had overlooked a bad connection in their fiber-cable system that messed up their timing by just enough to make it look like the neutrinos were going faster than light, which they probably weren’t. It’s all rather fuzzy with overlapping error bars, but the problem was significant enough to account for their faster-than-light result, which they have now admitted may have been in error. Several other similar experiments have not turned up any results indicating that neutrinos can exceed the universe’s speed limit either.
In these days of limited public resources (when were they ever unlimited?), what justification is there to spend many billions of dollars on things such as the Large Hadron Collider or the OPERA experiment? Judging by the fact that the torch of leadership in high-energy physics has clearly now passed from the U. S. to Europe, the American public seems to have answered, “None.” Some readers may remember the proposed Superconducting Supercollider planned for Texas, which was cancelled in mid-project in 1993 and never revived. If it had been completed, it would have easily surpassed the LHC in energy capability, and so we might have been hearing about the Higgs boson discovery from Waxahachie rather than Geneva.
The fact is, no single nation can claim that its citizens were responsible for the discovery. Thousands of Ph. D. physicists worked on the plans and experiments that made it possible, including hundreds from the U. S. High-energy physics today is a thoroughly international enterprise, and to do anything significant experimentally means to become a member of a huge team that resembles a multinational corporation more than a small university-style laboratory. This takes nothing away from the honors due to those who found the Higgs, but it does raise a question of responsibility.
CERN as an organization lent its name both to the Higgs-boson discovery and the announcement that neutrinos possibly traveled faster than light. Some would say that, hey, this is the way science works, and further checking indeed revealed that the faster-than-light discovery was in error. While I have no realistic doubt that the Higgs-boson discovery is legitimate, checking it may take anywhere from years to forever if you want to do it with another accelerator, because the LHC is the only show in town, that is, the world. Of course there are many different experiments that can be done with the LHC to demonstrate the Higgs, so it’s not like we had only one instrument reading, for example. But the point here is that CERN is becoming something of a monopoly in the high-energy-physics business. And monopolies may try not to act like they’re monopolies, but it’s not always easy.
When scientists such as those at CERN are asked to justify their arcane projects, they generally reply that physics, like many other scientific pursuits, is ultimately a cultural activity, and has to be its own justification. Some people paint beautiful paintings, others discover beautiful particles. From the viewpoint of engineering, I have to agree, because it has been a long time since a discovery in the realm of high-energy physics has led to any major practical applications. Probably the last time this happened was in the 1930s, when Lise Meitner and her colleagues discovered nuclear fission. That led to the development of atomic weapons and nuclear energy, both of which had consequences that are still with us today. Beyond that, however, I can’t think offhand of any consumer or industrial products that intrinsically rely on muons or neutrinos or quarks or any of the other members of the subatomic zoo discovered since then.
This doesn’t mean that practical applications will never come along. But they appear to have slowed down, certainly, and so I have to agree that experimental high-energy physics is just like observational astronomy: done for the beauty of the thing, and not for any practical uses of the knowledge that may result.
Still, a billion dollars is a lot of money, and I hope that CERN and organizations like it remember that they exist only by permission of a tolerant public. Incidents like the mistaken announcement of faster-than-light neutrinos do nothing to enhance their reputation, and so I hope that further checking takes place the next time a surprising result like that shows up, and also that the physics worker bees pursue their goal of confirming the Higgs boson with one-in-a-million certainty. That’s only several thousand dollars per chance, if you want to think of it that way.