• Question: What different theories did you experiment or created.

    Asked by lampton1905 to Joel, Kristian, Tim, Venus, Zachary on 20 Nov 2013.
    • Photo: Tim Hollowood

      Tim Hollowood answered on 20 Nov 2013:

      So I am a theoretical physicist and I work on the fundamental theories that describe all the particles and their interactions. The biggest problem is to fit gravity into the framework. That turns out to be a very hard problem that Einstein tried to solve but couldn’t. Now we have a theory that seems to do it called string theory. It’s very radical because it say that particles are actually tiny strings, think elastic band. Different vibrations correspond to different particles and the cool thing is that gravity in right in there. But it’s a tough theory to solve and I’m part of a global effort to understand it.

    • Photo: Kristian Harder

      Kristian Harder answered on 20 Nov 2013:

      My job is to do experiments, and thus the only theories I come up with are to explain why the hell this stupid experiment is not working right now. (Of course it’s only “stupid” and “hell” as long as it isn’t working. Once we managed to fix it, it’s back to being a “wonderful” and “exciting” kind of apparatus. 🙂 ) This is many levels below working on string theory, as far as theorizing goes, but it needs to be done anyway. Our experiments are so incredibly complex machines that it takes many people working around the clock to do nothing but keep them running. And if it’s not working properly, it can sometimes take a long time to figure out why not, and in process of trying to understand what is going wrong, people come up with theories almost as complicated as string theory. 🙂
      But most of the time the experiment is running, and then it is recording data from all sorts of particle collisions. It’s a very general purpose experiment. We try to catch anything happening with elementary particles that might be interesting. And once these data have been recorded, everyone starts sifting through them to check their own favourite theory, or to measure something specific. I personally spent some time looking for a weird cousin of the Higgs boson that would fly through half of our equipment without being seen at all, and then would suddenly pop up in an unexpected place. It’s quite hard to see something like this because it’s happening in an unexpected place, but I and my colleagues came up with procedures anyway, checked them on a detailed simulation of the experiment, and then concluded that we could see such particles if they exist. But unfortunately they don’t seem to exist. I guess I’ll be looking for something different next time. 🙂

    • Photo: Zachary Williamson

      Zachary Williamson answered on 21 Nov 2013:

      I’m an experimental physicist, so I don’t come up with theories. I do test them though.

      The one I’m currently testing and exploring is something called neutrino oscillation. Neutrinos are a type of fundamental particle: they can’t be subdivided into smaller parts. They’re very interesting because they are extremely light and interact with almost nothing, so finding out stuff about them is hard.

      They also do this thing called neutrino oscillation. There are 3 different types of neutrinos (called flavours), and neutrinos can seemingly change their flavour at will. This is really odd, and wasn’t predicted in our standard models of particle physics, so we want to know more about it.

      What my experiment is doing, is measuring the precise probabilities of one of these flavour types (muon flavour) oscillating into another flavour type (electron flavour). Finding out this probability will enable us to significantly improve our existing theories of the neutrino.

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