LHC Lunch

Meet Shannon Walch

Predictions and particles

Shannon Walch remembers a particular lab in high school physics. She and her fellow students had to determine where a ball would land on the floor after it rolled off a ramp and mark the spot with a coin. To Walch’s surprise, about half the class was able to make the prediction correctly based on minimal measurements and simple algebra.

This, Walch thought, was different from the memorization her other science classes required. It was logic. Her tests questions were of the format:  Given only a sheet of equations, predict the outcome of a situation. “Physics drove me nuts,” because it was the hardest to figure out, she said.  When she did, though, the sense of accomplishment was all the better for it.

The Highland, Utah, native began seeking more right away, getting a bachelor’s and master’s degree in physics and moving to graduate school at the University of Michigan. Two years in, after finishing her course requirements, she left for CERN to join her Higgs analysis group in person at the ATLAS collaboration. There she studies collisions that emulate the first split seconds after the big bang to search for the particle thought to give subatomic particles mass. “There’s so much to learn in physics,” she said, “You really just scratch the surface with a bachelor’s degree.”

The job is tough. In a recent project, Walch had to edit software for ATLAS that would account for how gravity was deforming wires in the muon detectors. “Yes, it’s that sensitive,” she said. “And that is a service work task, the bare bones of what you have to do. That’s easy physics.”

Generally Walch has to know detailed information about not only the physics phenomena she is analyzing, but also computer programming and all about how the detectors work before she can even begin to discuss her work with other people, she said.  Although she’s been doing the same tasks for a year, she’s still learning new things.

Fortunately, she’s never far from an expert. Being CERN-based is particularly advantageous for students, Walch said, because almost all the meetings and people she needs are right here. One exception is her advisor; he’s still at Michigan. He visits often, however, and firmly believes that CERN is where his students should be, rather than working on cutting-edge science from a distance.

Still, particle physics has taken Shannon many places other than CERN. She’s attended three physics summer schools: one in New Mexico, one at Fermilab in Illinois and, most recently, one in Romania. Each lasted for two weeks and consisted of lectures on advanced topics such as accelerator physics or specific theories. “I enjoy going to them,” she said, “They’re more helpful after you’ve been in the field for a while because they’re a crash course.”

Ultimately, Walch says summer schools provide a thorough overview of what’s happening in particle physics. This helps to put all her nitty-gritty work into perspective. Plus, she said, “You get to meet your colleagues.” Walch still sees people around CERN who she met three years ago at her first summer school.

Now, nearly finished with her doctoral degree, Shannon most likes the weird world of the quantum, “the very unpredictable, don’t-try-to-explain-to-your-grandparents-over-dinner-because-it-won’t-work type of thing.” Although this seems to contradict the nature of the straightforward, well-defined inclined planes and metal balls that originally drew her to the field, she said, “We can still make predictions… We just have to ask the right questions.”  She is in the right place to find some answers.