This sounds a bit like alchemy, but researchers have created matter/antimatter particle pairs using light and gold – but instead of a philosopher's stone, what the team needed was a particle collider.
The collision happened in the Relativistic Heavy Ion Collider (RHIC) located at Brookhaven National Laboratory. A team there smashed together nuclei of gold atoms to create high-energy photons. In turn, those photons were used to create a stream of electrons and positrons – the antimatter version of the electron.
The idea that light can be turned into matter is based on Einstein’s famous equation, E=mc2. Back in 1934, physicists Gregory Breit and John A. Wheeler first described the hypothetical possibility of colliding light particles to create pairs of electrons and positrons. As reported in Physical Review Letters, the STAR collaboration demonstrated that this can be done.
“In their paper, Breit and Wheeler already realized this is almost impossible to do,” a member of RHIC’s STAR Collaboration Zhangbu Xu said in a statement. “Lasers didn’t even exist yet! But Breit and Wheeler proposed an alternative: accelerating heavy ions. And their alternative is exactly what we are doing at RHIC.”
The gold ions in this experiment are made exclusively of the nucleus, stripped of all its electrons. The RHIC can accelerate these gold ions to a whopping 99.995 percent of the speed of light before making them smack into each other in some pretty weird physics states. However, the most important thing for this experiment is the production of gamma-ray photons.
Some of these photons can interact with each other, leading to the formation of electron-positron pairs – just as predicted almost 80 years ago.
“Our results provide clear evidence of direct, one-step creation of matter-antimatter pairs from collisions of light as originally predicted by Breit and Wheeler,” explained Daniel Brandenburg, who analyzed the data for the collaboration. “Thanks to RHIC’s high-energy heavy ion beam and the STAR detector’s large acceptance and precision measurements, we are able to analyze all the kinematic distributions with high statistics to determine that the experimental results are indeed consistent with real photon collisions.”
A different approach has shown that getting matter and antimatter out of light is doable in the last few weeks, and further investigations will continue to expand on how we can turn energy into matter.
