College of Science News
UTA researchers win $1 million grant to build detector to search for the origins of the universe
Physics researchers at The University of Texas at Arlington have won a $1 million grant from the U.S. Department of Energy to build a detector that may offer a key insight into the lingering mystery of the universe’s matter-antimatter imbalance.
The new detector will be integrated into an international physics experiment called Neutrino Experiment Xenon TPC (NEXT), which was conceived by David Nygren, UTA Presidential Distinguished Professor of Physics, and is being carried out in northeastern Spain at the Canfranc Underground Laboratory.
“With this project, UTA is competing strongly with teams from Stanford University, the University of California-Berkeley and the University of North Carolina on one of the main outstanding questions in particle physics and cosmology: Why are we here?” Nygren said. “If matter and antimatter were produced equally in the early universe — as the Standard Model of Physics requires — then almost all of the matter should have been annihilated by an equal amount of antimatter, with only a tiny amount of each surviving. But we would not exist. So, why do we?”
UTA researchers are devising a new type of detector for the NEXT project that could prove that the subatomic particle the neutrino and its antimatter particle, the antineutrino, are exactly the same.
To do so, they are focusing on a specific radioactive decay, the transition of one type of atomic nucleus to another, releasing energy and new particles. More specifically, UTA researchers are looking at a very rare form of decay called double-beta decay, where a nucleus emits two electrons and two antineutrinos at the same time. They are using a specific isotope of xenon gas for this search.
If the neutrino is in fact its own antiparticle, then the two antineutrinos could annihilate each other inside the nucleus, resulting in what is termed a neutrinoless double-beta decay. A discovery of this decay mode would strongly support the theory of leptogenesis, which predicts precisely the overall excess of matter in the universe as a whole and posits that the neutrino and antineutrino must be the same particle. Further, leptogenesis shows why we are here.
“If we observe that no neutrinos are emitted during double-beta decay, then the neutrino must be its own antiparticle, which would be a major Nobel-class discovery,” said Ben Jones, UTA assistant professor of physics, who co-leads the project with Nygren. “The difficulty is that double-beta decays only occur a few times a year in a ton of xenon gas, so our detector has to be extremely sensitive.”
When a xenon nucleus double-beta decays, it produces an ion of barium. UTA researchers have already demonstrated the effectiveness of a novel biochemistry technique that uses fluorescence or the emission of light to identify a single barium ion. Identifying the birth of a new barium ion will eliminate all the troublesome radioactivity processes that might otherwise mimic the true double-beta decay.
The researchers also plan to integrate the detection of single barium ions as they scale up to a detector containing a ton of high-pressure, purified xenon gas in which the electrons from the decay are very accurately measured.
Nygren and Jones’ lab has had a very successful year, bringing in more than $1.8 million in new grants. Among the first to congratulate the researchers was Alexander Weiss, professor and chair of the UTA Department of Physics.
“These new grants reflect the outstanding quality and originality of your proposed work and the potential of these projects to make fundamental contributions to advancing mankind’s understanding of the origins of the universe as we know it,” Weiss said. “The projects also reflect UTA’s strategic theme of data-driven discovery and will provide opportunities for our physics students to engage in international projects at the highest level.”
UTA is now actively participating in all of the current important international physics projects — upgrades to the Large Hadron Collider’s ATLAS experiment at CERN, planning for the International Linear Collider in Japan, the Deep Underground Neutrino Experiment (DUNE) with the Fermi National Accelerator Laboratory in Illinois, the IceCube experiment at the South Pole, and NEXT.