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from the and-hummingbirds-should-not-fly dept.
The apparent symmetry between matter and antimatter is puzzling scientists at the European Organization for Nuclear Research (CERN):
One of the great mysteries of modern physics is why antimatter did not destroy the universe at the beginning of time.
To explain it, physicists suppose there must be some difference between matter and antimatter – apart from electric charge. Whatever that difference is, it's not in their magnetism, it seems.
Physicists at CERN in Switzerland have made the most precise measurement ever of the magnetic moment of an anti-proton – a number that measures how a particle reacts to magnetic force – and found it to be exactly the same as that of the proton but with opposite sign. The work is described in Nature [open, DOI: 10.1038/nature24048] [DX].
"All of our observations find a complete symmetry between matter and antimatter, which is why the universe should not actually exist," says Christian Smorra, a physicist at CERN's Baryon–Antibaryon Symmetry Experiment (BASE) collaboration. "An asymmetry must exist here somewhere but we simply do not understand where the difference is."
Previously: Evidence Mounts that Neutrinos are the Key to the Universe's Existence
Matter-Antimatter Asymmetry Confirmed in Baryons
LHCb Observes an Exceptionally Large Group of Particles
Possible Explanation for the Dominance of Matter Over Antimatter in the Universe
(Score: 1) by Tara Li on Thursday October 26 2017, @06:24PM (3 children)
As the Wikipedia article mentions, these three processes are not sufficient to explain the entire disparity necessary for the current universe to be in existence. There is much left to be discovered. But they do point in at least one direction where more information might be found. But the physicists would dearly love find something else different - antimatter falling away from matter would be wonderful, since it would open whole new realms of questions. As far as I know, none of the current theories suggest that antimatter would act that way, so a lot of new work would need to be added to the current theories of gravitation.
(Score: 3, Interesting) by Anonymous Coward on Thursday October 26 2017, @06:37PM (2 children)
photons are their own anti-particle.
photons are affected by gravity just like Einstein predicted.
anti-matter reacts with matter, and the resulting energy is twice the rest-mass of the matter.
therefore anti-matter has positive rest-energy (or rest-mass), and it will be affected by gravity just like Einstein predicted.
while no experiment has confirmed this, and it's hard to imagine when we will have experimental confirmation, I really don't see why we should speculate before the results are in, especially since nothing else hints at anti-gravity effects.
(Score: 2) by HiThere on Thursday October 26 2017, @11:53PM (1 child)
Actually, IIRC anti-protons kept in storage rings need to compensate for gravity to avoid losing them via collisions with the bottom of the storage ring...which is fairly direct evidence.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Friday October 27 2017, @07:15AM
oh, thank you. I didn't know about that.
I always assumed that whatever anti-matter is confined is too hot for these kind of effects to be measured.
(i.e. " magnetic field required to control brownian motion is much stronger than magnetic field needed to compensate Earth's pull").