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Scientists set a strict limit on the electric asymmetry of nuclei, moving closer to solving the puzzle of the matter-antimatter imbalance.
A deuterium nucleus is like a spinning top. If the charges inside are unevenly distributed, the top tilts in an electric field. This tiny skew is called an electric dipole moment. At the COSY facility, physicists accelerated deuteron beams in a magnetic ring and watched for any tilt of the spin axis.
The experiment's sensitivity is equivalent to noticing a needle's point shift by the width of a human hair from ten kilometers away.
Result: no tilt. Instead, they set a record limit: less than 2.5×10⁻¹⁷ e·cm. The hunt for the electric dipole moment is key to one of the cosmos's greatest mysteries. If elementary particles had an intrinsic asymmetry, it could explain why after the Big Bang matter didn't completely vanish upon meeting antimatter. Such an asymmetry goes beyond the Standard Model and could be the solution. The experiment proved the method works. Now even more sensitive measurements are on the horizon.
The sensitivity is like noticing a razor blade tilt by the width of an atom from a football field away.
In Isaac Asimov's 'The Last Question,' the theme of missing antimatter doesn't come up, but his science fiction is permeated with a sense of the universe's unresolved asymmetries.