Most of us are familiar with the well-known subatomic particles that make up the universe: protons, neutrons, and electrons. But James Battat, associate professor of physics, is curious about a much lesser-known particle, the neutrino, and the Gordon and Betty Moore Foundation is helping him unlock some of its mysteries. In October, Battat became one of 16 scientists—and the only one from a liberal arts college—to receive a grant of $1,250,000 over the next five years to support his research on this elusive subatomic particle.
You’d be forgiven for never having heard of neutrinos; little is yet understood about them. What we do know is that neutrinos are the second most abundant particle in the universe (after the photon), they do not carry a charge, are nearly—perhaps totally—massless, and can travel at close to the speed of light. They are also incredibly difficult to detect.
But Battat hopes to change that. In 2020, he joined an international project called the Deep Underground Neutrino Experiment (DUNE), which extends, quite literally, from the Sanford Underground Research Facility in Lead, S.D., to Fermilab in Batavia, Ill., 800 miles away. The experiment will employ the world’s most intense neutrino beam, stationed at Fermilab, and utilize two detectors, one at Fermilab and the other at the Sanford facility. The goal is for this equipment to detect the neutrinos coming from the beam and allow scientists to study their properties.
In order for the technology to detect the neutrinos, it must be incredibly sensitive. Enter Battat and his team. With help from the Moore grant, Battat is building detector technology called Q-Pix that aims to provide the sensitivity needed to detect and study neutrinos and other types of matter in the future.
As Battat puts it, Q-Pix is “a two-dimensional grid of sensors—we’re talking hundreds of millions of sensors—that are very close together.” His lab at Wellesley is busy designing and testing the electronics. “We make smaller-scale benchtop prototypes that we can run to make sure that the circuits are functional. And if everything looks good here, then they could be deployed [in DUNE],” he says.
Q-Pix is an extraordinary undertaking for an undergraduate institution. “One of the really exciting and also daunting aspects of this Moore award has been that all of the other recipients were principal investigators at universities with grad students and postdocs, except Wellesley,” says Battat. “They’re giving this opportunity to us. We better show up.”
He is not tackling the project single-handedly. One of his closest collaborators, Jonathan Asaadi, is at the University of Texas at Arlington. Battat also has the help of several Wellesley students. “The group that I’m working with now is absolutely incredible,” he says. “We have seven students and one postbacc, Nora Hoch, who graduated last year and has stayed on to be a research assistant. Nora is absolutely incredible, both as a scientist and as an advisor to the students in the lab.”
But why study neutrinos in the first place? They have been termed “ghost particles” because they pass through matter—even the entire Earth—without interacting with it in any way. “You have billions of neutrinos going through your thumbnail every second. … They just go through your body as if it wasn’t there,” says Battat. That doesn’t mean, however, that it isn’t worth understanding how these particles function, if only to gain “a deeper understanding of our universe,” Battat says. In fact, neutrinos may be key to unlocking the mystery of how our physical world came to be.
Scientists have long been puzzled that there is more matter than antimatter in the universe. They believe that when the universe was in its nascency, it was made of equal parts matter and antimatter, which annihilate when they come into contact. So, logically, after each matter-antimatter particle pair annihilated, we should have been left with no physical entities in the universe. Yet here we are, on a planet, surrounded by matter.
Some physicists theorize that neutrinos may have played a role in offsetting the balance between matter and antimatter, creating an abundance of physical things in the universe. But uncovering the truth starts with detecting these ghostly particles—perhaps with some help from Battat and his students.