A physicist from the University of Cincinnati and his research partners from around the world conducted an experiment in Switzerland to look for evidence that might help explain one of science's most baffling questions.
UC College of Arts and Sciences Associate Professor Philip Ilten led an international research team in developing a new particle detector that ran experiments at the world-famous CERN Large Hadron Collider outside Geneva.
The custom-made detector was built in large part by students and installed deep underground in the massive accelerator's tunnels so it could capture novel data from long-lived particles hurled at nearly light speed around its nearly 17-mile loop.
Physicists say only 5% of the total mass of the universe is made up of planets, stars and other visible material. The rest is composed of a mix of dark matter and dark energy.
Dark matter is called dark because unlike normal matter it does not absorb or reflect light. Nevertheless, physicists have identified its existence through its gravitational effects, modifying motion of galaxies in the universe and stars in the galaxies.
Ilten's team was able to record several weeks of data in the nick of time before particle accelerator experiments at CERN were shut down to install scheduled upgrades in a process that could take four years. But Ilten said the project demonstrated a proof of concept that could justify the creation of a larger, more sensitive detector.
"This experiment went from the ground up here at UC. I'm excited it worked as it did," Ilten said.
UC Professor Philip Ilten assembled a team of student physicists and engineers for an experiment on dark matter at CERN by researchers from around the world. Photo/Provided
Hunting for elusive particles
Growing up, Ilten wanted to be an astronaut. He keeps a signed photo of moon-walker Buzz Aldrin in his office - a present from his grandparents. He became a licensed pilot while he pursued his second passion, physics.
"It is amazing to go from an idea on paper to something where you have taken data. It's something that, as a particle physicist, I never expected to do," Ilten said.
The project, called CODEX-b, is an effort to hunt for elusive particles to answer new physics beyond the standard model that describes the particles and forces at work in the universe.
"We think most of the matter out there is dark matter. We have no idea what it is," Ilten said. "None of the particles in the standard model can describe dark matter."
So researchers are looking for possible new ones using a suite of custom particle detectors.
"The Large Hadron Collider is like looking for a needle in a haystack," Ilten said. "But with the other detectors, you always get the haystack with the needle. This detector filters almost everything out."
It has been an extraordinary opportunity. The people on the experiment should feel tremendous satisfaction.
Philip Ilten, UC physics professor
The collaboration involved more than 50 researchers across Europe and North America, including six UC doctoral students, UC Associate Professor Conor Henderson, and UC Professor Michael Sokoloff. But by CERN standards, CODEX-b represented a relatively small experiment."
The researchers needed to build a custom particle detector, so they turned to UC's College of Engineering and Applied Science. (See From UC co-op to world traveler .)
UC engineering students Zarria Gray and Silviu Dobrescu worked with physics students and UC microelectronics engineer John Markus and lab tech Andrew Volz in the Physics Department's machine shop to build the detector, ship it in parts to Switzerland and assemble it more than 300 feet underground in the massive particle accelerator.
The students said it was a chance to work on a meaningful research project that had enormous logistical challenges.
"I think it will be a legacy moment in my life," Gray said.
UC's detector is composed of multiple panels arranged like layers in a cake to record particles hurtling around the Large Hadron Collider at nearly the speed of light. Photo/Philip Ilten
UC students collaborate on complex detector
Dobrescu was uniquely qualified to contribute to the project. He grew up making things like carbon fiber resin dispensers using new technology like design software. And he has a more than passing familiarity with the subject matter from his father, a particle physicist.
"At the end of the co-op application, it said you'll be working at CERN. I jumped out of my seat," he said. "I felt like I won the lottery."
Experiment establishes proof of concept
But on installation day, the cargo elevator was out of commission. They had to decide whether the sensitive detector could be lowered 300 feet by crane.
"We were nervous about this because they did such a great job making the modules, but they weren't designed to be picked up," Ilten said.
Ilten credited UC's David Northacker who built its sturdy frame.
The UC team recorded a video of the crane gently lowering the detector to the floor of the cavernous space.
"As a physicist you quickly realize why you need engineers," Ilten said.
Frequently asked questions about UC's dark matter research
What is dark matter? right arrow down arrow
Dark matter is subject of intense scrutiny among physicists who suspect that it explains why rotating galaxies haven't torn apart from centrifugal force. Physicists say dark matter accounts for 27% of the universe. But to date dark matter has been impossible to observe apart from its suspected gravitational effects.
Why do physicists study dark matter? right arrow down arrow
Dark matter could provide insights into the origins of the universe along with answering fundamental questions about physics that exist outside the standard model.
How does a particle accelerator work? right arrow down arrow
Accelerators use electromagnets to hurtle two beams of particles of elements such as hydrogen or lead in opposite directions through three increasingly larger circular accelerators before they enter the main 17-mile collider tunnel at a speed of more than 670 million miles per hour - or just shy of the speed of light. When the particles collide, they generate new particles such as the Higgs boson that researchers can observe and study with detectors.
What is UC learning about dark matter? right arrow down arrow
UC physicists are learning a lot about dark matter from experiments at CERN and other particle accelerators around the world. They theorize that dark matter accounts for 27% of the universe and does not emit, absorb or reflect light. And researchers are also using advanced space telescopes to try to observe the effects dark matter has on galaxies.
UC Professor Philip Ilten assembled a team of physics and engineering students to build a detector to hunt for particles that might provide answers about dark matter. Photo/Provided
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