BEIJING, Nov. 19 (Xinhua) — In a recently published paper, researchers asked the question: What would it mean if antimatter was the gateway to the dark universe?
Measurements of the universe to date show that much of the mass of the universe appears to come from “dark matter”, an invisible matter that interacts with conventional matter through the law of universal gravity. Despite great efforts, scientists have yet to detect dark matter directly. They tried many different methods, such as the PVLAS detector team at Italy’s National Institute of Nuclear Physics trying to find particles called axion. This is an imaginary subatomic particle that many consider to be a candidate for dark matter. By studying how axes interact with antimatter, the team hopes to find potential clues about dark matter.
The axis may be only the second most promising candidate particle for dark matter, after the Weak Mass Interactive Mass Particle, or WIMP. The particles are still in the theoretical stage and have not yet been discovered. In fact, the theoretical prediction of the axes has an incredibly small mass (only one in 50 billion to 50 millionths of electrons), and scientists first came up with the concept to solve the problem of CP conservation in particle physics. Later scientists realized that these particles might explain the extra mass in the universe.
While exploring dark matter particles, scientists are also trying to understand antimatter. Just as ordinary matter is made up of ordinary particles, antimatter is made up of antiparticles. As an extension of the antiparticle concept in particle physics, antimatter is a bit like the “evil twin” of matter: each subatomic particle has a corresponding antiparticle of the same mass, but the opposite charge, when particles and antiparticles meet, they attract each other, collide and fully convert into light, while releasing enormous energy. This process is called annihilation. Antimatter is not particularly rare, they occur in the typical atomic decay process on Earth, can also be artificially manufactured in the laboratory, but in today’s visible universe, antimatter is much less than conventional matter, this apparent positive and negative matter asymmetry has become one of the biggest puzzles in physics.
Christian Smorra, lead author of the paper and a researcher at the Japan Institute of Science and Chemistry (RIKEN), said scientists generally believe that dark matter interacts with matter and antimatter in the same way, but “this hypothesis has not yet been experimentally proven.” Because in atomic physics, the exploration of dark matter uses “material detectors” rather than antimatter detectors. Perhaps antimatter interacts with dark matter in a different way than ordinary matter.
Researchers in Japan, Germany, Switzerland and the United States are using cern’s (CERN) ‘baryon-Anti-Heavyweight Symmetry Experiment, or BASE. CERN’s antiproton decelerators can generate and slow down antiprotons and trap them in extreme vacuums through BASE. In 2017, the international team made three months of accurate measurements of these antiprotons to see how they functioned in magnetic fields. Now, scientists have re-examined the data to look for changes in antiproton spin. Spin is an internal nature of particles that make them a bit like a quantum version of a spinning gyro. The interaction with the axis, the theoretical dark matter particle, may change the way particles rotate around the axis of rotation.
This strategy of searching for axes has an added benefit: if dark matter interacts with antimatter differently from ordinary matter, the axis may help explain why there is far more matter in the universe than antimatter.
According to the new paper, published in the journal Nature, the researchers found no evidence of the existence of the shaft. In dark matter studies, such results can be said to be the norm. But in this age of physics, where all the obvious things have been discovered, scientists must spend a lot of time removing attributes that dark matter does not have, and hope to eventually find out from all these invalid results.
This is an important particle search process. “I’m glad that someone is looking at axial coupling beyond the axial-photon coupling,” said Chanda Prescod-Weinstein, an assistant professor of physics at the University of New Hampshire. In other words, scientists are finally trying to find axes that interact with ordinary particles, rather than focusing solely on the interaction symons and light particles.
Although the study still hasn’t given definitive results, the scientists’ search is not over. “Future work should focus further on axial-antiproton coupling,” Gianpaolo Carosi, a physicist at Lawrence Livermore National Laboratory in the United States, wrote in a commentary in the journal Nature. Look for evidence of the interaction of axial dark matter and other antimatter forms, such as electron antiparticles. “
The next step for the team should be to improve their measurement sensitivity, Says Karosi. What we do know about axes is that they are very small in mass, but they are possibly of a large range, and the charge and spin are zero. In any case, scientists’ exploration of dark matter will continue. (Any day)