Monday, 16 July 2012

The Higgs: Why do we need it, why were we looking for it in the first place and what do we do now?

Last week, we talked about what the Higgs boson did and how. However, there is more to it. It is fine knowing what something does, but $13.25 billion and almost 4 years has been spent using the greatest particle physics machine to look for this particle, so why is it so important?

I saw a brilliant line in an article on this subject a couple of days ago and it sums up the whole situation almost perfectly:
The impact of the discovery for the Average Joe is not going to be huge. It is massive for physics, because it is an extra fact. And there is nothing scientists like more than an extra fact. 
I feel I can pretty much leave it there. However, it is not entirely spot-on. The Higgs has some sort of value as a discovery, especially for particle physicists. And as our knowledge of the universe increases our ability to control what goes on around us also increases. You may not see the results of this discovery directly, but I promise, it will be revolutionary in the end.

Anyway, enough faffing around, lets talk about why physicists have been getting worked up about this brilliant particle since the 1960s.

The Higgs itself is actually not very important. The only reason we needed to find it was because it signalled the existence of something else, the Higgs field. The actual thing that is interacted with by particles with mass. I can feel you slipping through my fingers already so lets get to the interesting stuff. The main reason that we looked for the Higgs is that it is the last piece of the standard model. So let me explain that one first.

The Standard Model is the most advanced physical theory we have yet. It describes three of the four forces in the universe and tells us of every particle that we can observe today, as well as a few others. It has its limitations, it can't describe gravity for example, but it is the closest we have to a unified theory of everything. It took the last century to form.  

You can think of it as a machine. If you took the state of the whole universe, the particles, forces and fields within it and put that into your machine. It would then shoot out equations that described these particles and how they acted. However, if we included mass in the original picture, the machine broke, it just straight up didn't work. So physicists played around with the machine. Eventually a few separate groups of scientists, including Peter Higgs (the others being Philip Warren Anderson; Higg's partners Robert Brout and Francois Englert; Gerald Guralnik; C. R. Hagen, and Tom Kibble) came up with the idea of the Higgs mechanism. This meant that mass was not put in at the beginning, but instead this mechanism became part of the machine, and Hey Presto! Particles had mass! (I took this analogy from MinutePhysics, a brilliant youtuber, who has done two videos explaining the Higgs.)

However, the vast majority of the particles in the Standard Model had been observed in experiments by the 1970s and by 2000 the Higgs was the last one left. This discovery was such a huge deal because it could have proven whether or not the Standard Model is, for want of a better word, right.

The Higgs field is specifically involved in another part of the standard model, in one of the forces it describes. The force is called the weak force and chances are, you don't know what it is. There is a reason for that. The force can only work over a really small distance, about the diameter of a proton. Why is this? Because the carriers of the particles decay really quickly. And why is that? Because they have a really high mass! The force is very similar to one we see everyday, the electromagnetic force, but the observations were so different. The more we know about mass, the more we know about the reason the weak force is like this.

What about elsewhere? Will this result impact anything other than the two (rather large) fields I've already talked about? Disappointingly, it doesn't seem like it. There is a chance that it could be important in the research of dark matter, and the more we learn, the more we can discover, but in the immediate future, the Higgs may have to move over. But maybe that is the best bit. Now we have a somewhat finished Standard Model and a Higgs field, we can move on. The wonders of supersymmetry, dark energy and dark matter are just around the corner and looking at writing this article, I am reminded of a quotation by that brilliant man, Richard Feynman, on which I will end.

"Physics is like sex: sure, it may give some practical results, but that's not why we do it." 

We hope you enjoyed this post. We are excited to see the many developments that come after this brilliant discovery.

Ned Summers

If you you want to get in touch you can follow and mention us on twitter, @theaftermatter, email us at or search "The Aftermatter" on Facebook.

Check out our last two posts:
The Higgs: What is it, what does it do and have we found it? - The recent announcement at CERN has gotten a lot of physicists very excited, but what does it do?
The Physics of Field Athletics: Hammer Throw, Angular Momentum and what if everyone in the world spun around at the same time? - Why does a hammer-thrower spin before they throw?

What are we posting about next:
The Physics of Cycling: Lets Talk About Drag - We are back to the sports posts! Why do cyclists, in team events, cycle so near to one another? And how big is the difference it makes?

If you have ideas for posts we would love to heard them. Contact details are above.

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