The God Particle: A Disclaimer

Enlarge this image toggle caption Fabrice Coffrini/AFP/Getty Images Fabrice Coffrini/AFP/Getty Images

Particle physicists are at it again. Two weeks after I posted here on results from Fermilab on the possibility of a new force of nature, the rumor mill is again abuzz with speculation. This time the grape vine carries word that none other than the Higgs particle has been found at the Large Hadron Collider (LHC), the behemoth particle accelerator housed at CERN in Geneva, Switzerland. My co-blogger Adam Frank posted a quick note on this on Monday. I'd like to dive a bit deeper into it today.

Call it "physileaks": A leaked report from the LHC has surfaced and is getting underserved publicity. The report notes a bizarre signal picked up by the LHC's Atlas detector at masses around 115 times the proton mass. A CERN spokesperson has played down the claims, and is quoted by the Associated Press saying that it "is probably nothing."

First, I'd like to tell the real story behind this extremely unfortunate name "God Particle." As some of you may know, The God Particle is the title of a popular science book by Nobel Prize winner Leon Lederman, who was Fermilab's director for many years and thus my boss when I was a postdoctoral fellow there. According to Leon, he wanted to call the book The Goddamn Particle because nobody could find the thing. However, his editor discouraged him from the title, suggesting that The God Particle would sell many more copies. This is the story that Leon tells us.

In any case, the name stuck. Of course, the particle has nothing godlike about it. It's a hypothetical particle, part of the so-called Standard Model of particle physics. Its main job is to give masses to all other particles. I guess, in this role, it does have something of a centralizing influence, although nothing quite divine. Its real name, the Higgs boson, honors Scottish physicist Peter Higgs who, in the 1960s, worked on perfecting the details of the mass-giving mechanism.

The elusive Higgs is the missing piece in the Standard Model. Hence the great interest in finding it, or something like it. If you google "Higgs found" you will notice that rumors of finding the Higgs occur fairly often. Before you accuse particle physicists of being flaky (they are nothing of the sort), it's important to understand how the particle physics community works.

There are tens-of-thousands of particle physicists working in all corners of the globe. In fact, the World Wide Web was invented at CERN as a means to facilitate communication between them. Information must travel fast and be shared among the largest number of people possible. Huge projects such as those in particle accelerators involve thousands of scientists, engineers and technicians, what physicist Freeman Dyson once called "Napoleonic Physics." So, when an unexpected (or long predicted) signal is detected, many people know about it quickly. As the excitement mounts, it's almost impossible to avoid premature leaking of information. People talk, write and post comments in blogs. The media finds out and asks: What can we make of this?

Here is the wonderful thing about how science works. In the long run, it doesn't matter. An initial bump on the data will set off alarms, but it only marks the beginning of the action.

Thousands of people will mull over the results, more data will become available and carefully analyzed, discussions and countless meetings will unfold, and only when there is a very strong consensus will the official claim of a discovery be made. In numbers, an official discovery in particle physics corresponds to a six-sigma deviation, that is, an event that has only one chance in 500 million of being a fluke. So, the path from the initial "Wow, look at that bump in the data!" to "We have found the Higgs particle with a mass of X!" is very long indeed.

Would it be exciting to find the Higgs? You bet it would! Ever since I started my research career, I've been scaling up its hypothetical mass in the equations we use to model the physics of the early universe. What scientists at Fermilab and CERN have done over the years is to obtain what we call "lower bounds" on the Higgs mass. We know, at least within the simplest version of the Standard Model, that it must be at least 120 times more massive than a proton, and not much more. So, the expectation is that if the Higgs is found, it will have a mass not much larger than that.

Of course, the Standard Model may be telling us only part of the story (and there are many reasons to believe that this is the case) or, even more interestingly, the Higgs may not exist. Both possibilities are tantalizing. After all, Nature doesn't really care much for how we model it, even if we tend to find our own ideas beautiful and compelling. Rumors or not, in the final analysis the data decide.