Zoya Vallari Receives 2024 Leona Woods Lectureship Award

Postdoctoral experimental particle physicist recognized for her contributions to neutrino oscillation experiments

Zoya Vallari

UPTON, N.Y. — The Physics Department at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory has named Zoya Vallari, a postdoctoral experimental particle physicist at Caltech, one of the spring recipients of the 2024 Leona Woods Distinguished Postdoctoral Lectureship Award. Vallari visited Brookhaven Lab to give a general-interest colloquium and a technical talk about her work on Tuesday, May 7, and Thursday, May 9, respectively.

The Leona Woods award was established in honor of renowned physicist Leona Woods to celebrate the scientific accomplishments of outstanding female physicists and physicists from other underrepresented minority groups, including the LGBTQ community — and to promote diversity and inclusion in the Department.

“I feel honored and happy to receive this award,” said Vallari. “Science is a team effort. We work in large collaborations. So, this award, in some ways, also belongs a bit to all my collaborators. But it is nice to be recognized for the contributions I have made. I am very humbled to be chosen.”

Vallari, who grew up in Allahabad, India, received her undergraduate degree in 2010 at St. Stephen’s College, New Delhi, and her master’s degree in physics in 2012 at the Indian Institute of Technology, Bombay. In 2018, she received her Ph.D. at Stony Brook University, where she worked on T2K, a Japan-based project that conducts experiments on neutrino oscillations.

‘The beauty of physics’

“The questions in physics that intrigued me were always the fundamentals: What are we made up of? What are the fundamental particles? What are the fundamental forces? How are they unified or not?” said Vallari. “These are the existential questions of physics.”

Neutrinos, one of the most abundant particles in the universe, have no charge and almost no mass, and they can change type, or flavor, as they travel. Neutrinos travel at near lightspeeds through matter — including the Earth and humans — every second. Neutrinos may be the reason we exist, and yet, they elude our full understanding.

“Neutrinos intrigue me because they break our intuitions. Neutrinos are unpredictable and mysterious,” said Vallari.

At Caltech, Vallari works on the flagship U.S. experiments studying long-baseline neutrino oscillations, including the NuMI Off-axis νe Appearance (NOvA) and the Deep Underground Neutrino Experiment (DUNE), both based out of DOE’s Fermi National Accelerator Laboratory in Illinois.

These leading-edge, international experiments emit intense beams of neutrinos through the Earth from one detector to another over long distances — 810 miles (1,300 kilometers) in the case of DUNE. The transmission allows scientists to study how the neutrinos oscillate, or change, from one kind of neutrino to another. It also helps scientists explore unanswered questions, such as the origins and nature of the mass of neutrinos.

Understanding the mass of neutrinos has significant implications for scientists’ understanding of the makeup of the universe. The origins of neutrino masses are closely tied to subatomic processes that took place right after the Big Bang.

When neutrinos travel, they change “flavors” from one kind of neutrino family to another. What makes neutrino oscillations interesting to scientists like Vallari is that this behavior was not predicted by the Standard Model of particle physics.

By using accelerator beams at long-baseline experiments, Vallari analyzes neutrino flavor transformations to determine the neutrino mass ordering, neutrino-nucleus interactions, how to design and build the next-generation neutrino detector, and how to develop high-performance computing for high-energy particle physics.

At Caltech, Vallari has had the opportunity to continue collaborating with T2K for the world’s first combined analysis of data from both contemporary experiments, NOvA, and T2K. Vallari is excited to share the first glimpse of these results during her colloquium and technical talk at Brookhaven Lab.

“Neutrino masses and the charge parity violation are entangled in the current generation of experiments,” said Vallari. “Using the two datasets from these two independent experiments helps us disentangle them.”

Charge parity violation, or CP violation, plays an important role in understanding the relationship between matter and antimatter in particle physics and in our universe.

“There are three kinds of neutrinos, and they change from one kind to another. That is interesting, and it has not been predicted by our theoretical motivations before,” said Vallari. “That’s the beauty of physics. I love things when they behave differently from expectations.”

A science rock star

Vallari herself could be considered unconventional. She did not grow up with a last name in India; she was simply known as “Zoya.”

“My parents decided against passing down their last names to me since, in India, last names often denote caste, and they chose not to perpetuate that system,” said Vallari.

However, publication and immigration officials were not on board with this idea, so she adopted a new last name in graduate school.

“I should have chosen to be a rock star instead,” joked Vallari, “Like Lizzo or Zendaya!”

In addition to her notable work on neutrino oscillations, Vallari is also an accomplished science communicator, recipient of multiple awards, and volunteer in her community, where she teaches a course on science and society for Pasadena’s underserved high school students.

“I like communicating science and try to honestly share my joy and excitement and break it down into fundamental basics,” she said. “It’s important to share the excitement we get from our research.”

When asked what role her upbringing played in her personal and professional trajectory as a scientist, she credits her parents, who both have a Ph.D.

“I was really encouraged to ask questions. No questions were off limits,” said Vallari. “So, I was an annoying child: ‘Why did this happen?’ ‘But why?’ I wanted to break down everything and understand the core.”

“I do think my strength remains asking questions at all levels, both in science and society at large,” she said.

Vallari’s talks

Vallari gave a nontechnical colloquium, titled “Exploring fundamental symmetries through elusive neutrinos,” at Brookhaven Lab on Tuesday, May 7, 2024.

In this talk, Vallari reviewed the current landscape of the results from the long-baseline neutrino oscillation experiments and presented the results from the new combined analysis of the data from the NOvA and the T2K experiments. Additionally, she highlighted how upcoming next-generation experiments are being designed to enhance the precision of these measurements to meet the target sensitivities needed to achieve these ambitious physics goals.

Vallari also gave a more technical talk, titled “Search for leptonic CP Violation: Insights from the contemporary experiments,” on Thursday, May 9, 2024.

In this talk, Vallari presented the latest results from the NOvA and the T2K experiments, providing a snapshot of the accelerator-based neutrino oscillation measurements. This joint analysis utilizes the advantageous complementarity of the two experiments, which is useful for breaking degeneracies in the individual measurements and provides world-leading constraints on neutrino mass-splitting. Moreover, she outlined anticipated milestones over the next few years leading up to the commencement of the next generation of long-baseline experiments towards the end of the decade.

About the award: highlighting ‘unique perspectives’

The Leona Woods Distinguished Postdoctoral Lectureship Award, established in 2017, is named for Leona Woods, one of a small number of female physicists who contributed to the Manhattan Project, and who later served as a visiting physicist at Brookhaven Lab from 1958 to 1962. Leona Woods Lectureship awardees are selected twice a year.

The award was established to celebrate the achievements of women and minority physicists and highlight the diversity of the scientific community. 

“We hope that the Leona Woods Lectureship benefits the careers of these physicists by giving them a chance to present both a general interest colloquium and an expert-level seminar,” said Award Committee Chair Peter Steinberg, a distinguished scientist in the Physics Department at Brookhaven Lab. “The Lectureship expands our horizons at the Lab by highlighting younger scientists who often have very different backgrounds and unique perspectives.”

The award committee chooses the winners based both on their scientific excellence and their commitment to service in their communities, whether mentoring younger colleagues or providing teaching and guidance to younger students.  

Nominees must be within seven years of earning their doctoral degree and have achievements in broadly defined areas of interest to the Brookhaven Lab Physics Department. These include astrophysics, cosmology, and experimental, theoretical, nuclear, or high energy physics.

To submit nominations, visit the Leona Woods Distinguished Postdoctoral Lectureship Award website.

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

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