Scientists have provided evidence for the existence of two physical phenomena predicted over 80 years ago. To do this, they used the STAR detector at the relativistic heavy ion collider RHIC.

Scientists working on the STAR detector at Brookhaven National Laboratory in the United States reported that they were able to obtain convincing evidence of two physical phenomena predicted more than 80 years ago – the formation of the matter directly from light and that magnetism can bend polarized photons in a vacuum. … The research results are published in the journal Physical Review Letters.

STAR physicists tracked interactions and looked for predicted electron-positron pairs. But such pairs of particles can be created, including with the help of short-term states of “virtual” photons. To distinguish real photons from virtual ones, the authors analyzed the regularities of the angular distribution of each electron in relation to its partner positron. These distribution patterns are different for pairs formed by the interaction of real and virtual photons.

The main discovery is that pairs of electrons and positrons – particles of matter and antimatter – can be created directly by the collision of very energetic photons, which are quantum “packets” of light. This transformation of energetic light into matter is a direct consequence of Einstein’s famous equation E = mc², which says that energy and matter (or mass) are interchangeable. Nuclear reactions in the sun and at nuclear power plants regularly convert matter into energy. Scientists have now converted light energy directly into matter in just one step.

The second result shows that the path of light passing through a magnetic field in a vacuum bends differently depending on how the light is polarized. This polarization-dependent deflection (known as birefringence) occurs when light passes through certain materials. (This effect is similar to how wavelength-dependent deflection separates white light into a rainbow.) But this is the first demonstration of polarization-dependent deflection of light in a vacuum.

Both results come from the ability of the RHIC STAR – Solenoid Tracker at RHIC – to measure the angular distribution of particles produced by grazing collisions of gold ions moving at near the speed of light.