PhD Candidate, Department of Physics
As a four-year old, AC Williams dreamed of joining NASA to help solve the mysteries of the Universe. With a National Science Foundation (NSF) fellowship to support him, Williams is helping to do so as a member of an international team dedicated to discovering and identifying the properties of dark matter. This discovery could unlock the key to further completion of the standard model of physics, an understanding of black holes and much more.
A high school science teacher sparked Williams’ interest in physics, “He did a fantastic job of showing me how physics ties into astronomy.” Williams went on to earn a BS in Physics from Buffalo State College and was accepted directly into the PHD in Physics program at UB.
“When I entered the graduate program, I had a nebulous idea of what I wanted to do,” explains Williams. After taking a class taught by Salvatore Rappoccio and learning more about his research on dark matter and its potential applications, he found a way to tie astronomy, physics, data analysis and programming together.
“I could tell AC had the requisite talent for data analysis at this level. With the right training, I knew he could easily do this. He has enthusiasm, he’s super helpful and he fits in well with our group,” says Rappoccio, associate professor.
However, there were already 10 graduate students working on the project, so university funding was not available for him.
Rappoccio provided mentoring and support, and he encouraged Williams to apply for the NSF Alliances for Graduate Education and Professoriate fellowship. This program seeks to improve pathways to the professoriate and success for historically underrepresented minority doctoral students, postdoctoral fellows and faculty.
“It’s a godsend,” says Williams, now in his fourth year of the PhD program. “In order to attend school, I had to take out loans and my only source of income was a minimum wage job."
Now that Williams has completed his coursework, the NSF fellowship provides a monthly stipend to help cover living expenses and he can focus on his work.
The Search for Dark Matter
When scientists talk about dark matter it sounds like a classic riddle: What matter is six times more prevalent than regular matter, but we can’t see it, touch it, taste it, smell it or hear it? Unlike the riddles we solved in grade school, scientists have been searching for answers to questions surrounding dark matter for the past 30 years.
Dark matter is the term used to describe material that does not absorb, emit or reflect light and therefore cannot be seen or even detected by electromagnetic radiation. Scientists have measured that most of the Universe is made up of this material (if we exclude dark energy), and its gravitational effects are necessary to explain the rotation of galaxies, the motions of clusters and more. Dark matter is assumed to be prevalent here on Earth as well.
Rappoccio, his team and thousands of other physicists think that the properties of dark matter will possibly be discovered by studying the collision of high energy particles and protons in the Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator. The LHC consists of a 27-kilometre ring of superconducting magnets with a number of accelerating structures to boost the energy of the particles along the way.
Located in Geneva, Switzerland, the Large Hadron Collider is managed by CERN, an international council of world-class physicists. CERN's main area of research is particle physics, the study of the fundamental constituents of matter and the forces acting between them. CERN’s engineers, technicians and scientists develop novel technologies and expertise contributing to applications in fields beyond high-energy physics, addressing global societal challenges in areas such as health and environment.
Rappoccio describes CERN as “a sub-city within Geneva” with thousands of people working on particle physics. “The excitement is undeniable. You live, breathe and talk about this work, it’s a weird subculture, but it’s really fun.” Williams was preparing to spend a year working at CERN when the pandemic hit; he is hoping to continue his work in-person at CERN when possible.
Speeding Up the Path to Discovery
With the help of computer simulations and analytics software, physicists analyze millions of collisions at the Large Hadron Collider to isolate specific events to study. Williams explains, “You have to have some way of sifting through tens of millions, potentially billions, of different events [at the LHC] to find the ones that have the characteristics you want to study. All of the code that we’re writing is to study a specific outcome of these collisions.”
Williams is responsible for data analysis, calibrations and software updates. He is spearheading a new workflow using column based analysis. While this technology has been used by corporations to manage big data, it hasn’t been widely applied to data analytics in physics.
“We have a code speed up at a factor of 100, meaning that it’s 100 times faster than it used to be. It used to take about three days to run all our data, now it takes an hour and a half,” explains Rappoccio. “AC wrote the code in a better way. There is a small but growing community of developers in our field using this software, and Williams is one of the best. He’s one of the pioneers and it is working extremely well so far.”
Williams is in constant contact with Rappoccio, team members who live in China, India, Australia and Switzerland and the primary developers who built the software. Coordinating meetings across time zones is a challenge, but the entire team is energized and focused. “Every day is a learning process,” he says.
Dark Matter and a Bright Future
Completing this project and writing and successfully defending his thesis are some of Williams’ short-term goals. With a PhD in hand, he has several potential career paths.
“If we don’t get any concrete results from this project, it just means that there is more work to be done,” he says. He could receive a postdoctoral appointment at UB or another institution to continue this work, or he could pursue a position at CERN, Fermilab in Chicago or at a similar research laboratory throughout the world.
Williams' long-term goals are inclusive and aspirational. “If we discover even just a small hint of a signal of new physics, I hope that it inspires other scientists—theoreticians and experimentalists—to actually look into something that is new. I want everybody to come together and help figure it out.”
And he hasn’t wavered from his original goal, “I would love to fulfill that childhood dream of having an office at NASA where I would continue my work on dark matter or black holes or other new physics things that we don’t even know about yet.”