Recent research published in Physical Review Letters proves that matter and antimatter can be created from energy, specifically light particles (photons). Thus, it provides a magnificently physical illustration of the world's most famous equation: E=mc2.
Einstein's equation describes how energy (E) is equal to mass (m) multiplied by the speed of light (c) squared. The study demonstrated that physicists at the Relativistic Heavy Ion Collider (RHIC), a facility operated by the Department of Energy's Brookhaven National Laboratory, were able to convert light particles, which are made up of energy, into pairs of electrons and positrons, which are made up of matter (matter being that which has mass). To be exact, positrons are antimatter; yet, antimatter has the same energy-mass equivalency.
The researchers created the matter-antimatter couples using gold ion beams. They took gold atoms, stripped away all their electrons to create positively charged ions, and then blasted the ions at ultrarelativistic speeds past one another (99.995 percent the speed of light, or roughly 186,000 miles per second).
Ions generate a powerful magnetic field that revolves around them. This magnetic field interacts with the perpendicular electric field, and the resultant electromagnetic field is composed of packets of information known as photons or light. As the ions pass through the particle accelerator, clouds of these photons accompany them.
Zhangbu Xu, Brookhaven Lab physicist and a representative of the RHIC’s STAR (Solenoid Tracker at RHIC) Collaboration, described the research project setup: “We have two clouds of photons moving in opposite directions with enough energy and intensity that when the two ions graze past each other without colliding, those photon fields can interact…” This interaction is responsible for the formation of pairs of electrons and positrons.
While a comparable finding was accomplished in 1997 at the SLAC National Accelerator Laboratory, the technique was more sophisticated and entailed additional stages at the time. This finding stands out as “clear evidence of direct, one-step creation of matter-antimatter pairs from collisions of light as originally predicted by [20th-century physicists Gregory] Breit and [John A.] Wheeler,” according to Daniel Brandenburg, a Goldhaber Fellow at the Brookhaven Lab.
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| "...full-energy collisions between gold ions at Brookhaven's... RHIC, as captured by the... STAR detector." |
Additionally, the work establishes a previously theoretical prediction about the interaction of polarised photons with empty space vacuums. In the twentieth century, physicists (particularly Werner Heisenberg, Hans Heinrich Euler, and John Toll) predicted that a vacuum of empty space would deflect specific polarised photons if the vacuum was polarised as well. This phenomenon, known as vacuum birefringence, has not before been detected in any Earth-based experiment.
Similar to how polarised sunglasses filter and absorb certain wavelengths of light, the vacuum plus magnetic field also blocks and absorbs certain wavelengths of light. This light is converted to electron-positron couples.
The researchers were able to determine this connection because “…the angular distribution of the [electron-positron pairs] depends on the angle of the polarisation of the light. This indicates that the absorption (or passing) of light depends on its polarisation…” as Chi Yang, a STAR colleague from Shandong University, puts it.
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