After a bit of a hiatus, Perimeter lectures are back. This month’s presenter was Melissa Franklin, Department Chair of Physics at Harvard. Franklin is a) an experimental physicist, and b) hilarious. Excellent combination for a public lecture.
Her talk was “Discovery of the Higgs Boson: Sweet Dream or Nightmare”, by which she meant Sweet Dream for experimentalists and possible Nightmare for theorists, though, as she quipped, they can come up with new theories in 4 or 5 days.
Although long enough in the States now to be relieved by the outcome of the most recent election (so say we all), she got in touch with her Canadian roots with a poppy and a hockey stick instead of a laser pointer. At one point she was gesturing with the hockey stick and carrying a wine glass, which, if you think about it, pretty much sums up Canadian physicists.
To the talk. Franklin said she didn’t really feel the Higgs field until she was walking home shortly after the big announcement in July that scientists were pretty sure they had it confirmed at the LHC. She suddenly was aware of it, and it’s been with her since. She has, by the way, been working on experimental science to find Higgs one way or another for 20-something years.
She was very good at bringing all of the science down to very pragmatic terms and analogies so that everyone could understand how they were able to find Higgs indirectly. In the end, it comes down to the fact that Higgs can couple with all kinds of particles and sub-particles. And, if it is not forbidden, it is compulsory (Feynmann). Meaning that every coupling that can happen, will happen. In the LHC, that means getting a big whack of protons creating enough data to break the Internet or run out of CDs. And because they can trace back the particles they see, they can find the Higgs (with slightly more math than that).
At the speeds they are travelling, it’s like the protons aren’t really protons when they crash, though, more like a stream of gluons, quarks and anti-quarks. What the scientists look for is a tiny bump at a certain wavelength. Let’s turn to the wineglass – if you make the wineglass “sing” by rubbing the rim, you are demonstrating a similar graph to what they look for in particles. In the case of the particles, it’s a bump that indicates mass and lifetime.
Two groups – one the French one (the “dark side”) and one Franklin’s team (ATLAS), saw the same bump in the same place and this is the Higgs mass they believe they have identified at around 125GeV.
Franklin got in several good jabs at the theorists in the house, though she did concede that both camps do a lot of drinking when they aren’t physics-ing.
As for what’s next, more experiments and working through what Higgs means to the Standard Model, supersymmetry and all those other small questions. LHC is shutting down for some tweaking and refurb soon which will allow them to throw things faster in their experiments.
Higgs may offer us insight into dark matter, and THAT would be a talk I’d like to see.
Interesting exchange during the question period, where a youngish woman asked Franklin what it was like to be the first tenured professor in Physics at Harvard. “Are you in Physics?” Franklin asked the questioner. “I’m at Perimeter,” she said. Franklin: “Then you know. The wonderful thing about people at Harvard is that they are all so sure of their own greatness that you’re not a threat. Each day, you just have to reset yourself”. Sad comment on the status of women in science today.
One final note: Greg Dick from Perimeter gave us an update on their recent survey about the public lectures. Apparently lots of people complained that if you aren’t available to get tickets between 9:00 and 9:03 on the Monday morning, you can’t get in. True, but what they’ve decided to do about it is run the “registration” for each lecture for 24 hours and then you are in a LOTTERY to get tickets. This is a classic example of listening to your customers (good) and then assuming you know what the solution is without asking them or exploring further. ALL LECTURES AREN’T EQUAL, GREG. What if there’s only 1 I really want to see, and now it’s up to your lottery as to whether or not I can go?
I thought the audience was going to storm the stage in outrage at this. We’ll see how long it lasts. We all have his personal email.