26 August 2012

Science Sunday: And God Said, "Let There Be Mass!"

It's Science Sunday, everyone! Woohoo!

I'd like to say a few words about what is likely one of the biggest scientific finds this century. That is the particle that is consistent with the Higgs boson. On 4 July of this year, ATLAS and CMS (two teams doing research at CERN), using data gathered by the LHC (Large Hadron Collider), independently confirmed finding a particle that is consistent with the Higgs boson. What exactly does that mean? Well, it means that this particle behaves like a Higgs, decays like a Higgs, quacks like a Higgs, but hasn't been tested enough so we can't actually say it is a Higgs. For most of us out there that boils down to this: They found the Higgs boson. While that's not necessarily true, it's what most people, both those who are and who aren't scientists, believe.

So what exactly IS a Higgs boson? Well, I'm going to be one hundred percent honest with you: I haven't done any formal studying of it myself, and the mechanism behind it is a bit complex so I can only go so far in an explanation. That being said, I've done a little reading on the subject of the Higgs, so here's what I seem to understand in a qualitative, possibly handwavey, manner.

The Higgs boson is an excitation of a field that is present everywhere in the universe at all times. It's a whosawhat in the wheresawhen now? Let's think about it another way. Imagine that there's a medium all around you, let's say it's jell-o. Let's say that you were born in this jell-o and for as long as you can remember the jell-o has always been there no matter where you go and what you do. Everyone and everything exists in this jell-o. Considering the fact that you were born in the jell-o and have grown in it, you can easily move through it and it doesn't impair anything in your life. In fact, you don't really notice it's there at all because it's always been there.  Well, the jell-o is kinda like the Higgs field. It's there, but we're not really aware of it, so we don't really experience it as anything. So we can imagine doing things in this jell-o, and though it don't ostensibly impair our actions, it certainly affects them.

Now imagine shaking the jell-o so that different ripples appear. Shake it a little bit and small ripples are created. Shake it more and bigger ripples. These ripples eventually dissipate back into the jell-o's original shape. This is kinda like exciting a field. The metaphor is by no means perfect, but I hope it sheds a little light on the situation.

 So then, to say a Higgs boson is an excitation of an ever pervasive field is sorta like saying that it's the result of that field rippling. Okay, great, so what does the Higgs boson DO exactly? It gives things mass. Mass to me and you? Well, yes and no. Yes, the Higgs is theoretically responsible for the mass of certain particles, but it contributes so little to the mass of a human that it's basically negligible in everyday life. Most of our mass is the result of what's called the strong nuclear force. Nevertheless, it is the Higgs that gives mass to the W± and Z bosons, explaining why they have mass and why a photon doesn't.

What are these other particles I just mentioned? Well, these are particles that serve as force transporters in a sense. W± and Z bosons are the transporters of the weak nuclear force, which means that they in some sense carry this kind of force. Without them, there wouldn't really be a weak nuclear force, which is the force that dominates radioactivity. Photons are the transporters of the electromagnetic force. Without them everything would be dark because there'd be no light since there'd be nothing "carrying" it. These three types of bosons (W+, W-, and Z) along with photons should be massless due to a kind of symmetry in one of our leading models of physics (the Standard Model), but the bosons have mass. This is because the Higgs boson, via the Higgs Mechanism, makes it more energetically favorable for the W± and Z bosons to have mass, "breaking" the symmetry between them and the photon. To understand this energetic favorability, let's say that the W± and Z bosons and the photons are on a hill that's too small for them all and they're balancing precariously. The Higgs boson kicks the other three bosons off the hill and, now on the ground below, the bosons have much more space and are free to go where they want. It's kind of like that.

So, by finding our particle consistent with the Higgs boson, we've basically determined how certain particles develop mass. Not only that, but, by finding this particle we end up confirming the correctness of our Standard Model. This will lead to more elegant models that sum up how our universe works more and more succinctly. Also, it proves that we, as a race, are pretty awesome when we feel like it, and whether you care about the science or not you can at least care about that.

Anyway, if you have questions feel free ask by leaving a comment. I'll do my best to answer them, but considering I don't particularly understand the math behind this and only kind of understand it qualitatively, no promises. I highly suggest you go read about it yourself if you're so inclined, or ask someone at your friendly neighborhood college physics department. If I've made any egregious errors, please let me know. I'd rather not spread misinformation. And if you just want to say a couple random things, that's great too. Lastly, tune in Thursday for another fun filled blogisode of Theater Thursdays!

See you shortly!

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