January 5, 2022
https://www.eurekalert.org/news-releases/939319
Introduction:
(EurekAlert) As part of an experiment to measure—to an extremely precise degree—the charge-to-mass ratios of protons and antiprotons, the RIKEN-led BASE collaboration at CERN, Geneva, Switzerland, has found that, within the uncertainty of the experiment, matter and antimatter respond to gravity in the same way.
Matter and antimatter create some of the most interesting problems in physics today. They are essentially equivalent, except that where a particle has a positive charge its antiparticle has a negative one. In other respects they seem equivalent. However, one of the great mysteries of physics today, known as “baryon asymmetry,” is that, despite the fact that they seem equivalent, the universe seems made up entirely of matter, with very little antimatter. Naturally, scientists around the world are trying hard to find something different between the two, which could explain why we exist.
As part of this quest, scientists have explored whether matter and antimatter interact similarly with gravity, or whether antimatter would experience gravity in a different way than matter, which would violate Einstein’s weak equivalence principle. Now, the BASE collaboration has shown, within strict boundaries, that antimatter does in fact respond to gravity in the same way as matter.
The finding, published in Nature, actually came from a different experiment, which was examining the charge-to-mass ratios of protons and antiprotons, one of the other important measurements that could determine the key difference between the two.