By smashing particles together at close to light speed inside an atom smasher, scientists created a never-before-seen type of matter: an anti-hypertriton.
The particles the fuel gives off, which travel faster than the speed of light in water, can as a result produce a particular type of light, harmless in itself, called Cerenkov radiation.
One possible explanation for these positrons is the mutual annihilation of the matter and antimatter forms of atype of dark matter called weakly interacting massive particles, also known as WIMPs.