Higgs Boson Higgs Particle

Most of the science that gets reported in the media is directly to do with life: genetic engineering and the science of preventing illness and disease; GM crops and the science of improving food supplies; climate change and the challenge of preventing extinctions and disasters.

We’ve forgotten that, for a period from the 1920s to about the 1970s, it was physics that was making all the waves in the media: the discovery of the atomic structure; relativity; the atom bomb; the possibility of space travel.

If the Higgs particle is found, that “Golden Age” of physics could be about to return.

Since the time of Einstein, who died in 1955, physics has been slowly and, for the most part, quietly building up an increasingly complete picture of reality at its most fundamental level. At that time, the protons and neutrons of the atomic nucleus were known, the electrons orbiting it were well known, and the neutrino was finally confirmed in 1956. The mechanisms of radioactivity were widely studied and gravity of course had been studied since Newton. Electromagnetism was identified as a force as far back as the nineteenth century by James Clerk Maxwell.

So physics understood that there were forces working on particles: electromagnetism (light); the strong nuclear force (which keeps atoms together); the weak force (which regulates radioactive decay) and gravity (which holds the universe together).

But the detail of these fundamental forces, these interactions (as they are often called by physicists), was not known. How did they work together? At first sight they look different and even mutually contradictory: electromagnetism means protons repel other protons – both having a positive charge – but the strong force means they bind together in a nucleus. Gravity is the weakest force but is holding everything together.

For the last fifty years, Physics has tried to look for ways to unify the forces. It’s been searching for the final theory, the Grand Unified Theory, or the Theory of Everything. Unifying everything means looking at how the universe works at a fundamental level and then trying to find the connections between apparently different things. 

Since 1960, electromagnetism has been unified with the weak force, making the electroweak force and the strong interaction has been confirmed by the discovery that protons and neutrons are made up of smaller particles called quarks.

These breakthroughs have been added to a growing view of fundamental physics called the Standard Model. In the Standard Model, which was first developed around 1967, fermions – key particles of matter, such as quarks, neutrinos and electrons – exist alongside bosons, which are mainly particles carrying forces.

So relationships between particles are at the heart of how physicists view the universe.

But there’s a very important gap in the Standard Model, which the collider at CERN is trying to find evidence for. The Standard Model predicts that there is another, massive (ie having mass) particle called the Higgs boson. It is named after the scientists who predicted it, Peter Higgs of Edinburgh University, who first described it in 1966. According to the theory, massless particles gain mass travelling through a Higgs field – a sort of “sticky” field, which glues itself to particles as they go through. The Higgs particle is a key part of this and would therefore help to explain mass, as well as differences between massive and massless particles.

If it existed, it would be literally everywhere in the universe.

The Large Hadron Collider at CERN in Switzerland is looking for the Higgs boson in its high-energy collisions of protons. It has been doing so since late 2009 and as yet there is no direct evidence of the Higgs boson. It is perfectly possible that there may yet be, and physicists are not yet panicking about the collapse of the Standard Model. It is also possible that if it does not exist, or cannot be confirmed, that there are alternative particles instead.

The search for a particle that could be at the heart of reality is ongoing. The LHC and the possibility of the Higgs boson makes this a very exciting time for physics, once again, and could lead us to a deeper understanding of what underlies everything. It would not explain everything, because there are still other areas that need to be explored, such as the questions around the strength of gravity, and how it fits in, but it would get us further on that road.