Unravelling the Higgs boson

a.k.a., the “god” particle!

by Atyab Calloo

Atyab Calloo is a PhD candidate at Polytechnique School of Montreal in Nuclear Engineering

Atyab Calloo is a PhD candidate at Polytechnique School of Montreal in Nuclear Engineering

So, let me just get something out of the way here, the “god” particle has nothing to do with god - or theology of any kind. The physicist who named it such wanted to use “goddamn” but his publishers would not have that; so he suggested “god” instead. But what he wanted to convey was the importance of this particle in physics and just how difficult it would be to demonstrate its existence.

What is it?

Now, let us talk about what it is. It is an elementary particle that is the manifestation of something called a Higgs field. To cut a very long story short — or in this case, a long theory that is beyond most people in this world, a Higgs field is why the particles in your body, the screen you’re reading this on, or anything in the Universe really, have mass.

Little bit of history

Finding this particle wasn’t easy. It was theorised in 1964 in three famous scientific articles by six authors, amongst which were Peter Higgs (after whom the particle is named) and Francois Englert who were awarded the Nobel Prize in Physics in 2013. These papers led to a 50-year-long search for the Higgs boson. However, back then, the technology to discover this particle was simply not there.

Figure 1 : Size of the LHC

Figure 1 : Size of the LHC

Small physics lesson

I promise this is the only equation I will write: 

Everyone knows this equation, right? This is Einstein’s equation saying that mass is equivalent to energy, and vice versa. The world around us is made up of atoms which are made up of protons, neutrons and electrons. They are stable particles, because they don’t ‘disappear’ after a small amount of time. The problem with other particles (like the Higgs boson) is that they are around for a very very very short time, which make them highly unlikely to be lying around in our back gardens. Sadly enough.

So what do we do then? I.e., how was it discovered?

We take the particles we do have and we smash them into each other! Because of the mass-energy relation, by smashing them, we can convert these particles to energy and this energy then decays to different particles of different masses (compared to the particles we started with). Simple concept but extremely hard in practice. Indeed, a huge particle accelerator/collider, with detectors and experiments along it, had to be built (see Figure 1 and 2), which was an enormous feat of engineering. This is the famous LHC (Large Hadron Collider) underground in Geneva, Switzerland.

Quick LHC facts, showing its complexity

• It tooks TEN years to build, in collaboration with over 10 000 scientists!

• When the particles collide, the temperatures can reach 100 000 times that of the surface of the Sun…

• …while the magnets used in the LHC have to be cooled to temperatures colder than deep space!

• The particles are accelerated to speeds close to 99.9999990 the speed of light.

• A whopping 170 computing centres in 36 countries are needed to analyse all the data generated annually.

Yay! They found it!

In July 2012, after sifting through, processing and analysing tens of petabytes (1 000 000 gigabytes) of data, the researchers at the LHC (more specifically the ATLAS experiment), announced preliminary results showing evidence of the existence Higgs boson. These preliminary results have since been confirmed, with more experiments. Finding proof of the existence of the Higgs boson is a huge step in understanding the fundamental nature of our Universe. 

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Figure 2 : A section of the LHC

Figure 2 : A section of the LHC

Figure 3 : ATLAS experiment showing the massive amount of detectors and the engineering

Figure 3 : ATLAS experiment showing the massive amount of detectors and the engineering

And hopefully, this nerdy science joke from Neil deGrasse Tyson now makes sense to you if it didn’t already before [2]:

“A Higgs boson walks into a church, and the priest says, 'I'm sorry we don't allow Higgs bosons to come to churches.' And the Higgs replies, 'But without me you can't have mass!”