Still Chasing the God Particle!

Physicists at CERN — home of the world’s most powerful particle accelerator — are bracing for a fresh assault on the tantalizing Higgs boson.

In 2012 they used CERN’s Large Hadron Collider (LHC) to generate subatomic debris that could be interpreted as traces of a single “God particle” (as the Higgs sometimes is called). (Don’t call it that around most physicists — they hate that nickname!)

The discovery capped decades of searching and brought a 2013 shared Nobel Prize to Peter Higgs, the theorist for whom the particle is named.

The LHC is a 17-mile circular tube, located at Geneva, Switzerland, in which protons collide at almost the speed of light. For its 2012 experiments, the LHC operated at 7 TeraElectronVolts (TeV). Translation: That’s a buncha-buncha energy! Enough to fry an egg, or (more likely) a medium asteroid.

The machine has been cooling down ever since, while undergoing upgrades and maintenance. All prepping it for its next round of experiments in 2015 at 13 TeV (nearly double the power).

This forthcoming run should provide never-before-possible insights into the structure of our universe, possibly including dark matter — something we’re pretty sure exists, but know next to nothing about.

Higgs: Why It Matters

So why did Leon Lederman, director-emeritus of Fermilab, annoy his fellow-physicists by dubbing this baby the “God particle”? Why is the Higgs so vital?

Answer: The Higgs particle isn’t important at all, except insofar as it provides tangible evidence for a reality much deeper — the Higgs field. The field, not the particle, is what matters. Here’s why:

Many elementary particles, such as quarks and electrons, have mass — some more, some less. Others, like photons in the wild, have none. For a long time, physicists could see no reason why any particle should have any mass. Lacking mass, particles would zip around at the speed of light, with no gravitational pull. There’d be no atoms — hence no galaxies, stars, or planets. No you and me!

Higgs and his colleagues filled the gap by postulating a hitherto unknown energy field — a field pervading all of space and time. In this model, any particle interacting strongly with the Higgs field picks up some of its energy in the form of mass. The more interaction, the more mass. Particles such as photons, lacking mass altogether, presumably don’t interact at all.

We might thus compare mass to the drag we experience in wading through molasses. A broad, beefy person would encounter far more drag (i.e., be more massive) than a skinny one. This isn’t a perfect analogy; but then, physics analogies never are.

Having a Field Day

The Higgs field made sense of equations that otherwise seemed senseless. But how to prove it? Let’s consider the nature of fields in modern physics:

Fields — not particles — are the basic realities of our material universe as currently understood. Forces such as gravity, light, magnetism, and others are secondary, outward effects of fields. The latter, however hidden they may be, are primary and underlying.

Details differ depending on whether we approach the topic through general relativity (the study of large-scale phenomena) or quantum mechanics (the study of the very small).

General relativity treats field effects as changes in the very shape of space and time. Quantum mechanics treats them as the interplay of energy packets (“quanta”) that can’t decide whether to be waves or particles. (More in a moment on this schizophrenic behavior.)

So what is a field? Ask a gaggle of physicists, and you’ll get lots of hemming and hawing that boils down to this: A field is a vacuum that can vibrate. In other words, the so-called spacetime continuum is never a featureless void, even when it seems empty:  That “emptiness” is itself a medium rich in physical properties!

Foremost among those properties is the capacity to transmit effects that correspond, in some ways, to what we know as waves or ripples. These in turn give rise to particles. No elementary particle is really a thing-in-itself: It’s just a splash or wiggle in its underlying field.

Physicists call this the wave-particle duality. That’s what I allude to above as “schizophrenic behavior”. Observe an electron (for example) one way, and it acts like a wave. Observe it another way, and it acts like a moving point or speck. This paradox is not something we can visualize using any familiar physical analogy: We can only model it mathematically.

The point is that every particle is really a disturbance in its underlying field. Space is alive with such fields — electromagnetic, gravitational, and many more — along with their associated particles. Is the Higgs field one of these? If so, it would be one of the most important and interesting, given its proposed role in conferring mass on particles arising from other fields.

To prove the Higgs field, one must find and identify the Higgs particle (boson). CERN scientists reasoned that by using the LHC to generate sufficiently violent collisions, they might shake the Higgs field just enough to create the barest quiver. That momentary ripple (viewed as a particle) would give them their telltale clue. It would travel hardly any distance; it would last for an inconceivably tiny fraction of a nano-second. It could be detected only by its after-effects.

This is what CERN achieved in 2012. It validated the Higgs field by — apparently — generating a Higgs “particle” (wave). More questions than answers? Sure; what else is new? As we know, it was enough of a grand slam to make Peter Higgs a Nobel laureate and to chalk up yet another historic first for CERN.

Just to be clear, CERN isn’t known only for its contributions to esoteric particle research. In 1989 it also invented this little gadget called the World Wide Web. Well, technically, Tim Berners-Lee invented it — but he did so as an employee of CERN, which then placed the technology in public domain.

So stay tuned: There’s a whole lotta shakin’ going on!