Leslie Rogers explores the mysterious imbalance of matter and antimatter

In 1963, Maria Goeppert Mayer became the second woman to win a Nobel Prize in physics for her work at the Department of Energy’s Argonne National Laboratory on the nuclear shell model. Goeppert Mayer is also well-known for proposing the idea of double-beta decay, a type of radioactive decay that, under certain circumstances, can provide insights into why excess matter exists in the universe.

Leslie Rogers became curious about the process of double-beta decay during her PhD in physics at the University of Texas at Arlington. She was specifically interested in neutrinoless double-beta decay (NLDBD), an extremely rare process that has never been observed in nature. Now, as a Maria Goeppert Mayer fellow at Argonne, Rogers is designing and testing methods to hopefully observe NLDBD for the first time.

“I’m thrilled to be able to continue Maria Goeppert Mayer’s work; I think she would have loved to be part of the experiments we’re doing now.” — Leslie Rogers, Argonne scholar

The Maria Goeppert Mayer Fellowship is an international award given to outstanding doctoral scientists and engineers to help them develop their careers in Argonne’s high-impact research environment. The fellowship honors Maria Goeppert Mayer’s exceptional contributions to science. It provides early-career scientists the opportunity to pursue their own research directions, with the support of a sponsor and up to three years of funding. Here, Rogers discusses her research to uncover the mysteries of NLDBD and what it means to be following in Maria Goeppert Mayer’s footsteps.

Why is studying double-beta decay important?

I’m part of an international collaboration called the Neutrino Experiment with a Xenon Time Projection Chamber (NEXT), where scientists are searching for NLDBD. A neutrino is a subatomic particle that has no electrical charge and a very small mass. We think that when an atom undergoes this type of decay, it emits two electrons but no neutrinos. If this is the case, it will help us understand why there’s so much more matter than antimatter in the universe.

We know there’s a ton of matter, but the Standard Model of physics states that there should be equal amounts of matter and antimatter, similar to how energy is always conserved. Because matter and antimatter particles are produced as a pair, they can destroy or annihilate one another when they come into contact. Something knocked us off that equilibrium. If we’re able to prove that NLDBD is real, it could demonstrate that a neutrino is a combination of both matter and antimatter, allowing it to be able to annihilate with itself. Ultimately, this means that we could start with an equal amount of matter and antimatter, but if antimatter annihilates with each other, then you can end up with more matter than what you started with.

What is your research focus at Argonne?

Part of my research at Argonne focuses on figuring out how to make large detectors that are sensitive enough to observe NLDBD. When an atom undergoes NLDBD, it shoots off two beta particles and knocks electrons off the other surrounding atoms. We can then transform those electrons into light, which I can record with a camera. The camera I use is extremely fast—it can snap pictures at the nanosecond scale, essentially providing us with a video of how the light changes over time.

Since NLBDB is so rare, we need a very large number of atoms, about 10²⁶, if we hope to see one of them decay over the span of 10 years. The detector is also extremely sensitive. Because there’s radioactivity everywhere all the time, the system I’m developing is able to distinguish whether we’re observing NLDBD or other forms of radioactive decay. The detector is also significantly cheaper than the other methods currently used to search for NLDBD.

What do you enjoy about your research?

I got my undergraduate degree from the University of Texas at Arlington, where I double majored in mechanical engineering and physics. I worked as an engineer for several years before going back to school for my PhD in physics. I love my research because I get to do a lot of hands-on experiments and develop new techniques. It’s a great way to use my background in engineering to figure out problems in fundamental physics.

What inspired you to apply for this fellowship?

Corey Adams, who is part of the NEXT team at Argonne, reached out to me and recommended that I apply for the Maria Goeppert Mayer Fellowship. The fact that it’s named after Dr. Goeppert Mayer is amazing. I’ve read all her papers that have to do with double-beta decay and nuclear shell models. I’m thrilled to be able to continue her work; I think she would have loved to be part of the experiments we’re doing now.

What do you enjoy about working at Argonne?

This fellowship has awarded me a lot of freedom in my research, so I’ve been able to pick up side projects outside of my main research. I really like the people I work with, too. People are constantly helping each other out by sharing their expertise as well as equipment for experiments. There are so many resources on site and so many experts I can reach out to with questions.

What do you enjoy doing outside of research?

When I’m by myself, I like to play with my cats and paint. When I’m with other people, I really like to do karaoke and play board games.

What advice do you have for early-career scientists?

A lot of teenagers I’ve interacted with seem stressed out about making the correct career choice immediately. I changed my career path from engineering to physics, and I’m very happy with my decision. My engineering background has helped me a lot, and there’s no knowledge that I’ve gained that was a waste. In general, everything you learn ends up benefiting you, so it’s fine to take some detours and follow what is interesting to you at the moment.