The Higgs boson is, if nothing else, the most expensive particle of all time. It’s a bit of an unfair comparison; discovering the electron, for instance, required little more than a vacuum tube and some genuine genius, while finding the Higgs boson required the creation of experimental energies rarely seen before on planet Earth.
The Large Hadron Collider hardly needs any introduction, being one of the most famous and successful scientific experiments of all time, but the identity of its primary target particle is still shrouded in mystery for much of the public. It’s been called the God Particle, but thanks to the efforts of literally thousands of scientists, we no longer have to take its existence on faith.
Why has the Higgs been the subject of so much hype, funding, and (mis)information? For two reasons. One, it was the last hold-out particle remaining hidden during the quest to check the accuracy of the Standard Model of Physics.
This meant its discovery would validate more than a generation of scientific publication. Two, the Higgs is the particle which gives other particles their mass, making it both centrally important and seemingly magical. We tend to think of mass as an intrinsic property of all things, yet physicists believe that without the Higgs boson, mass fundamentally doesn’t exist.
The reason comes back to something called the Higgs field. This field was actually theorized before the Higgs boson itself, as physicists calculated that in order for their theories and observations to jive, it was necessary to imagine a new field that existed everywhere in the universe.
Shoring up existing theories by inventing new theoretical components to the universe is dangerous, and in the past led physicists to hypothesize a universal aether — but the more math they did, the more they realized that the Higgs field simply had to be real. The only problem? By the very way they’d defined it, the Higgs field would be virtually impossible to observe.
The Higgs field was thought to be responsible for the fact that some particles that should not have mass, do. It is, in a sense, the universal medium which separates massless particles into different masses.
This is called symmetry breaking, and it’s often explained by way of analogy with light — all wavelengths of light travel at the same speed in the medium of a vacuum, but in the medium of a prism, each wavelength can be can separated from homogenous white light into bands of different wavelengths.
This is of course a flawed analogy, since the wavelengths of light all exist in white light whether or not we’re capable of seeing that fact, but the example shows how the Higgs field is thought to create mass through symmetry-breaking. A prism breaks the velocity-symmetry of different wavelengths of light, thus separating them, and the Higgs field is thought to break the mass-symmetry of some particles which are otherwise symmetrically massless.
It was not until later that physicists realized that if the Higgs field does exist, its action would require the existence of a corresponding carrier particle, and the properties of this hypothetical particle were such that we might actually be able to observe it.
This particle was believed to be in a class called the bosons; keeping things simple, they called the boson that went with the Higgs field the Higgs boson. It is a so-called “force carrier” for the Higgs field, just as photons are a force carrier for the universe’s electromagnetic field; photons are, in a sense, local excitations of the EM field, and in that same sense the Higgs boson is a local excitation of the Higgs field.
Proving the existence of the particle, with the properties physicists expected based on their understanding of the field, was effectively the same as proving the existence of the field directly.
Enter, after many years of planning, the Large Hadron Collider (LHC), an experiment massive enough to potentially falsify the theory of the Higgs boson. The 17-mile loop of super-powered electromagnets can accelerate charged particles to significant fractions of the speed of light, causing collisions violent enough to break these particles into fundamental constituents, and deform space around the impact point.
With a high enough collision energy, it was calculated that scientists could basically super-charge the Higgs boson, pushing it up into an energy state where it would decay in ways that we can observe. These energies were so great that some even panicked and said the LHC would destroy the world, while others went so far as to describe an observation of the Higgs as a peek into an alternate dimension.
Initial observations seemed to actually falsify predictions, and no sign of the Higgs could be found — leading some researchers who had campaigned for the spending of billions of dollars to go on television and meekly make the true-but-unsatisfying argument that falsifying a scientific theory is just as important as confirming it.
With a bit more time, however, the measurements began to add up, and on March 14, 2013 CERN officially announced the confirmation of the Higgs boson. There is even some evidence to suggest the existence of multiple Higgs bosons, but that idea needs significant further study.
So what’s next for the God particle? Well, the LHC just recently reopened with significant upgrades, and has an eye to look into everything from antimatter to dark energy. Dark matter is thought to interact with regular matter solely through the medium of gravity — and by creating mass, the Higgs boson could be crucial to understanding exactly how.
The main failing of the Standard Model is that it cannot account for gravity — one that could do so would be called a Grand Unified Theory — and some theorize that the Higgs particle/field could be the bridge physicists so desperately desire.
In any case, the Higgs is really only confirmed to exist; it is not yet remotely understood. Will future experiments confirm super-symmetry, and the idea that the Higgs boson could decay into dark matter itself? Or will they confirm every tiny prediction of the Standard Model about the Higgs boson’s properties and, paradoxically, end that entire field of study once and for all?