A University of Hawaiʻi at Mānoa project to advance the knowledge of the universe and understanding of its origin and dark matter, received a major boost from the National Science Foundation. The three-year, $568,586 grant will enhance the Cosmic-Ray Antinuclei (CRA) group’s work to help the Alpha Magnetic Spectrometer-02 experiment (AMS-02) at the International Space Station.
Under the guidance of Department of Physics and Astronomy Associate Professor Philip von Doetinchem, the project will use the measurements of cosmic-ray antinuclei (anti-equivalent of regular nuclei of atoms) to identify the nature of dark matter and other new astrophysical phenomena, and could be used with other cosmic-ray species to understand cosmic-ray production and propagation in the galaxy.
The work will improve the understanding of antinuclei formation and interactions, using existing data from AMS-02 and results from the fixed-target SPS Heavy Ion and Neutrino Experiment (NA61/SHINE) at CERN (European Council for Nuclear Research).
Future of cosmic-ray antinuclei
Doetinchem and other researchers recently published an article in the Journal of Cosmology and Astroparticle Physics, which details the current progress of studying cosmic-ray antinuclei and its breakthrough in physics.
Doetinchem noted that researchers rely on messengers to learn about the galaxy; the most common is light from stars. However, their approach uses heavier charged particles, also called cosmic rays, which undergo different interactions on their way to Earth than light.
In particular, the researchers are focusing on very rare cosmic antinuclei. Antinuclei have been artificially produced on the ground in particle physics experiments, but have not been observed in space. The advantage of studying these scarce particles is that they allow researchers to study very rare production processes, and one of these processes could be the annihilation of dark matter. The understanding of dark matter is one of the towering questions in physics because it is about five times more abundant than regular matter, but not much more is known about its nature at this time.
More on UH Mānoa’s CRA group
Along with its work to assist AMS-02, Doetinchem’s CRA group is involved in several other activities to advance using cosmic-ray antinuclei as messengers for dark matter. Doetinchem is the project scientist for the new General AntiParticle Spectrometer (GAPS). This NASA experiment will be launched in a series of long-duration balloon flights at high altitude over Antarctica to search for low-energy cosmic-ray antinuclei starting in 2022. UH Mānoa undergraduate student Layne Fujioka developed an augmented reality app, funded by UROP, that illustrates how the GAPS experiment works.
The group is also actively using Mana, UH’s High-Performance Computing Cluster, to simulate antinuclei formation, and interactions with Earth’s atmosphere and the geomagnetic field. For example, a study led by graduate student Anirvan Shukla used this facility for thousands of computing years to study the formation of antinuclei, which was recently published in Physical Review D.