Harry Cliff - The Higgs boson, dark matter and other mysteries of the universe

The Higgs boson is so important to our understanding of particle physics that it was hyperbolically referred to as the “God Particle”.

About Harry Cliff

"I am a particle physicist at the University of Cambridge, a populariser of science and a science writer.

I work on an experiment called LHCb, which is a giant particle detector on the Large Hadron Collider at CERN, where we study elementary particles – the basic building blocks of our universe."

When protons collide

I work on the Large Hadron Collider, which is the world’s largest particle collider. What it does is simple and brutal. It takes particles called protons and smashes them into one another with lots of energy.

There’s a long tradition in particle physics of these sorts of experiments where you smash particles into one another. The reason for doing this is perhaps not what you would expect. Particle colliders are sometimes described as atom smashers, which conveys the idea that we’re using these machines to smash atoms apart to see what’s inside them. But that’s not really what colliders are for, because we know what’s inside atoms. We discovered that in the 20th century.

Colliders like the Large Hadron are better described as matter factories. You accelerate particles to very high speeds because, at those speeds, particles carry huge amounts of energy. When you collide them, that kinetic energy is converted into new matter. So, you’re actually making matter or making new particles from energy. When two protons collide, many of the particles coming out of that collision didn’t exist before; they were created in the collision.

In other words, this is a way of studying the sorts of objects that can exist in the universe. When you get to really high energies, you’re probing energy densities, temperatures and conditions that haven’t existed in the universe in any large amounts since about a trillionth of a second after the Big Bang. You’re probing the kinds of things that were going on in the very first moments of the universe. This is why these experiments are so interesting.

Key Points

• July, 4th 2012 was a pivotal day in the history of particle physics. At a special event, scientists working at the Large Hadron Collider confirmed they had detected the Higgs boson.
• The Higgs boson interacts with a quantum field known as the Higgs field, giving mass to particles like electrons and quarks. Without this interaction, electrons and quarks would never bind together to form stable atoms.
• While the Higgs is the last missing piece of the Standard Model, it opens up a whole new set of questions and problems for particle physicists to puzzle over.