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Melissa Franklin is the first woman ever to achieve tenure in the Harvard physics department. She is an experimental particle physicist who has been working on the Collider Detector at[…]

Why is a group of brilliant scientists spending millions to find the smallest particles in the universe? As it turns out, they will be able to teach us a lot about our own origins. Physicist Melissa Franklin explains how.

Question: What does a particle physicist do?

Melissa Franklin: First of all, there’s really two kinds of particle physicists. There’s the kind you see on the back of book covers and those are usually theorists. They just sit in their office and write down theories of things. And try to tell experimentalists what to do. And there are experimentalists who actually do the experiments and they try not to listen to the theorists. So there’s two. And I’m the latter, I’m an experimentalist. So, what do we do? We decide we’d like to know something about the universe, and in particular we’d like to know something about the universe at a very small scale. So, we’d like to know not only exactly what the smallest particles that make everything up are, like quarks and leptons, but we would like to know, what’s their relation to each other? How do they interact? How did they interact a long time ago, for instance, in the beginning of the universe? How are they going to interact in the future? And so we do these experiments which are really fun. It’s really like controlling thing incredibly. We’re very big into controlling things. We take proton beams and proton beams and we smash them together and we build an enormous $500 million detector to measure every microsecond what happens. So that’s what we do, we study the symmetries of the universe and how they get broken.

Question: Why should an everyday person be interested in particle physics?

Melissa Franklin: Well, everyday people, it’s amazing what they’re interested in actually. Everyday people are quite interested in a lot of things that you might not think. Every day people are interested in the beginning of the universe and you can’t understand the beginning of the universe like the Big Bang, unless you understand particle physics. It’s all particle physics really. And actually you can’t understand much. Here’s the thing. Particle physics right now is at a scale which is much smaller than the – a distance scale much smaller than the scale of an atom. Much smaller. So you would think well atoms are the smallest things they need to worry about and humans should worry about atoms, by the way. Atoms really do affect your everyday life, they affect biology, they affect – chemistry and everything. Right? So, what happened is as particle physics we went to the atom, we understood everything about it, and we just kept going. And it may not be relevant to Biology, but it may be relevant to something in the future. I’m not exactly sure what, but it certainly – for instance, if it’s relevant to the beginning of the universe, I have to say, the beginning of the universe is also relevant to Biology. Depending on what happened at the beginning of the universe what the initial conditions were of the universe, it tells us about the future. Strangely.

Question: What is the Higgs-Boson Particle and why is it important?

Melissa Franklin: Well, first you can’t describe what it is, it’s just an idea. We have this model; it’s called the standard model. The reason there’s so much depression in particle physics in the past 20 years is because the standard model seems perfect. That is, we have a model and for many reasons, the standard model, we keep testing it, we keep building accelerators, we keep doing experiments. The standard model predicts something; we keep finding it to be true. So, that’s depressing. In this standard model there’s one missing piece. There’s a symmetry that we think – we see this as being a broken symmetry, so you can imagine someone that is symmetric, but then one eye is like half an inch lower than the other eye. And we go, why? Why is that? And we say, well we think we know. We think we know why it is. One possibility is there’s this Higgs-Boson. It’s something it’s a particle which interacts with all the other particles in such a way as to make them move more slowly, let’s say. Have mass, be harder to push around. So, there’s one theory that this Higgs-Boson should be able to be seen soon at high energies and we’re going to find it. So there’s a whole bunch of people who are really looking for the Higgs-Boson. And we haven’t found it yet and I have to say that all the indirect evidence says we should have found it already but we didn’t. And then there’s a whole bunch of other people who are feverously and wonderfully saying, “Look, if we don’t find the Higgs-Boson, it's even more interesting.” The only worry is that if we do find it, the standard model is right. If we don’t find it, we may never make us – build us another accelerator. So, it’s kind of complicated.

Recorded on: October 21, 2009

Image: dominikf, Flickr