Crease: What's the Higgs deal?

Robert P. Crease is chairman of the philosophy department at Stony Brook University. His most recent book is "World in the Balance: The Historic Quest for an Absolute System of Measurement."

Physics has made global headlines twice this fall. One was a report last week from CERN, the international laboratory outside Geneva, of "tantalizing hints" of the existence of a subatomic particle called the Higgs boson. The other was an announcement in September that particles called neutrinos, created at CERN and clocked as they raced to another lab in Gran Sasso, Italy, move faster than light.

Both reports are dramatic. Particles moving faster than light would overturn the theory of relativity. The discovery of the Higgs would cement the foundations of the standard model of particle physics. Both theories are comprehensive tools for understanding our universe.

But the physics community has reacted in diametrically opposed ways to the developments. The news about the Higgs generated widespread and genuine excitement. The prospect of faster-than-light neutrinos met with skepticism and jeers.

What's happening? Do scientists simply believe what they expect and reject what they don't? Are they acting irrationally?

Hardly.

Theories aren't speculations. They're like maps that tell you how to get around in a place you're mostly familiar with; they connect with experience. Like maps, theories don't have to be complete to be good, and they change as new equipment changes the territory. Theories organize what we know and help us look for what we don't.

Relativity, for instance -- which includes the requirement that nothing travels faster than the speed of light -- has been a reliable guide in exploring the universe for a century. Why abandon it because of one reported sighting of something that doesn't fit? Most physicists assume there's just something wrong with the faster-than-light experiment. It's already the butt of jokes: "The calculations were done by visiting Americans who still don't get the metric system"; "Something exceeds the speed limit in Italy, and this is news?"; "The photons thought it was a school zone"; and my favorite: "To prove particles can travel faster than light. Why did the neutrino cross the road?"

The standard model, meanwhile, explains nearly everything seen thus far in the landscape of the subatomic world, which physicists explore with instruments called particle accelerators. The things in this landscape consist of 12 matter particles, called fermions, which interact with each other via force-carrying particles called bosons. The standard model also describes how the universe evolved after the Big Bang. It's a reliable and almost complete map.

Almost complete, with one gaping hole. The theory suggests that a particle called the Higgs boson (named after an English physicist) belongs somewhere on the map, but -- frustratingly -- does not say exactly where. Physicists have combed the subatomic realm, without success. The Higgs should be created in accelerator collisions, then decay in a flurry of other particles.

Now, two groups of experimenters at CERN say they've spotted possible traces.

If more data clinch this discovery, the Higgs particle, for several reasons, is sure to be one of the major scientific discoveries of the 21st century.

First, it's a unique particle. In the standard model, it is associated with a field -- the Higgs field -- that explains why the known particles have mass. In the primeval universe, immediately after the Big Bang, all particles were massless and swarmed about in a featureless vacuum. The universe had a kind of uniformity that physicists call a symmetry.

A few fractions of a second later, the universe changed form in a transition akin to the way steam changes into water, or water into ice. The original symmetry was broken, and particles now began interacting with the Higgs field, which has permeated all of space ever since.

The oft-used analogy is that it's like what happens when a crowd at a concert is milling about -- and then the rock stars suddenly try to walk through. People flock to them, slowing the stars down, making them, as it were, "heavier." This "flocking," or symmetry breaking, is the work of the Higgs field.

In the simplest model of the Higgs field, it is associated with a particle -- the Higgs boson. There are strong reasons to assume the Higgs field exists, but what its particle looks like so far is unknown.

A second reason finding Higgs would be such a big deal has to do with the standard model itself. It has been pieced together over several decades, with contributions from scientists and labs worldwide. Last week's news from CERN could well be the first glimpses of the last cornerstone of one of humanity's greatest intellectual achievements.

Third, the CERN experiments were global efforts. Thousands of scientists in labs around the world, some on Long Island, built pieces of the detectors and are analyzing the data flowing from them. Brookhaven National Laboratory built several pieces of the Atlas detector and is the headquarters of the 43 U.S. institutions collaborating on data analysis. Over a dozen scientists and students at Stony Brook University are calibrating the energies of photons and electrons, a central component of the Higgs measurement.

Finally, this work complements other areas of science. Brookhaven's Relativistic Heavy Ion Collider, for instance, is a different kind of instrument studying conditions in the early universe. The research at RHIC involves a different epoch of the early universe than CERN's work -- a few milliseconds later, when another transition took place. Together, however, the CERN machine and RHIC provide scientists with a more complete portrait of the early universe.

Small wonder that Higgs jokes have been tame, not mocking: A Higgs particle enters a church. Priest: "We don't allow your kind here!" Higgs: "But without me, you can't have mass!"

Scientists are genuinely excited, even at what amounts only to "tantalizing hints." This work locates the next major landmark in an important and complex terrain, after a long and exhausting search in which many people took part. The discovery of the Higgs would mean that physicists can breathe a bit -- that they can be confident of their understanding of how matter gets mass, and that some form of symmetry-breaking indeed occurred in the early universe. It gives them confidence to look for physics beyond the standard model.

Like any important scientific discovery, it's at once the end of one chapter and the beginning of another.

And if the tantalizing hints turn out to be misleading, and the Higgs particle turns out not to exist, it doesn't mean the map provided by the standard model is bad. It just means that the territory is even stranger -- and therefore more interesting -- than we thought.