Q&A with Shao-Feng Ge: Planning the next wave of neutrino experiments

Shao-Feng Ge

The Neutrino Physics Center (NPC) at Fermilab brings together scientists from all around the world to investigate the elusive neutrino, a particle that could explain how our universe evolved.

One of the latest scientists to join the NPC community is postdoctoral researcher Shao-Feng Ge from the University of Tokyo and University of California at Berkeley. He received an NPC award to work with other neutrino experts in particle theory and experiments at Fermilab for three months.

How did you get into neutrino physics?

When I was in high school, I remember reading a short essay describing the use of neutrinos for telecommunication, such as communicating directly across Earth or contacting the surface from a deep underwater submarine. I didn’t understand any particle physics at that time, but it was a refreshing idea.

Then, when I was a third-year undergraduate student, I was thinking about the direction of physics I wanted to pursue when my advisor gave me information to read about neutrinos. I found neutrinos more and more interesting, and it has become one of the major topics in particle physics.

The importance of neutrinos is related to why matter would exist in our universe. In the ideal case, matter — including even us — should not exist in the universe, and this drives physicists crazy. Why does the world exist in the first place? That’s the big question. 

What attracted you to the Neutrino Physics Center?

Some of my collaborators in Japan are working on improving the precision of the T2K and T2HK neutrino experiments there in the hope of better understanding neutrinos. This would involve adding a cyclotron, a device to accelerate particles with an oscillating electromagnetic field, to the experiment. The addition of this piece of hardware would provide scientists with better measurements.

I decided to come to Fermilab and participate in the NPC fellowship program to collaborate with more scientists and possibly add this same technology to experiments here in the United States.

Fermilab is the center of neutrino physics, so I have been hoping to come here for ages, since the very beginning on my Ph.D. study almost 11 years ago, and now I have finally made it.

What do you enjoy about being able to work internationally?

I enjoy being able to be involved with many international labs because it keeps me and my work moving. I worked at the High Energy Accelerator Research Organization, or KEK, in Japan for two years before going to work at the Max Planck Institute for Nuclear Physics, MPIK, in Germany for three years. Every laboratory has different strengths and specialties, which in turn allows me to gain various skills and acquire new knowledge. Just by talking with someone, I can get the chance to learn something new.

What does your work as a neutrino theorist entail?

I work on models to expand our understanding of neutrinos, which come in three flavors, as we physicists call it: the electron, muon and tau neutrinos. There is mixing between the flavors, where one will spontaneously change into another. I make hypothetical models to predict the mixing pattern.

I’m also looking for novel ways to use neutrinos to discover new physics. In traditional neutrino experiments, neutrinos are produced with a certain flavor from a source. They then oscillate between flavors during the flight from the source to a detector. Finally, they scatter, producing other particles, when they reach the target material. By measuring the scattering of the particles produced, such as electrons and muons, we can reconstruct the characteristics of the incoming neutrinos that triggered the reaction.

Neutrino oscillation experiments cannot extract all types of information. What if neutrinos experience extra interactions unknown to us? We need new types of experiments.

One possibility for exploring this unknown information is to use the same technology we currently use in neutrino oscillation experiments but, instead of trying to reconstruct the information of incoming neutrinos, we try to understand what happens in the scattering process itself, especially if new physics appears in this process.

I’m planning to model these potential scattering processes and explore whether they can be investigated in current and upcoming neutrino experiments.

What do you like to do in your free time?

I don’t really have any hobbies. I work a lot, but I really like the work I do!