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Antimatter is a shadowy mirror image of the ordinary matter we are familiar with.
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For the first time, scientists have measured the forces that make certain antimatter particles stick together.
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The findings, published in Nature, may yield clues to what led to the scarcity of antimatter in the cosmos today.
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The forces between antimatter particles - in this case antiprotons - had not been measured before. If antiprotons were found to behave in a different way to their "mirror images" (the ordinary proton particles that are found in atoms) it might provide a potential explanation for what is known as "matter/antimatter asymmetry".
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( D5 y: P- `' zAt the beginning of the Universe, the Big Bang produced matter and antimatter in equal amounts. But that's not the world we see today: instead antimatter is extremely rare.
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Some phenomenon must have led to the overwhelming dominance of matter; scientists have their theories, but the evidence remains elusive.
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3 \* j7 K; B; `" x"Although this puzzle has been known for decades and little clues have emerged, it remains one of the big challenges of science," said co-author Aihong Tang, from the Brookhaven National Laboratory in New York, US.
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"Anything we learn about the nature of antimatter can potentially contribute to solving this puzzle."
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