Evidence of an unusual particle—which, oddly enough, is also its own antiparticle—has been found by scientists. It was first proposed eighty years ago, but it appears now that it might actually be true.
Researchers from Stanford University and the University of California conducted the study that was written in the journal Science.
The idea that a particle could have its own antiparticle was first proposed in 1937 by the Italian scientist Ettore Majorana (who disappeared without explanation in 1938). He said that protons, electrons, and neutrons are among the particles in the fermion class that should have distinct antiparticles. Majorana particles are the name given to these particles later on.
An antiparticle is a particle that has the same mass as a regular particle but opposing electric and magnetic characteristics. For example, the antiparticle of an electron is a positron. The two destroy each other if they come into contact.
In this work, two thin films of quantum materials were stacked in a cold vacuum container and an electrical current was passed through them. The top film was a superconductor, whereas the bottom layer was a magnetic topological insulator.
Then, by moving a magnet across the stack, the scientists were able to change the electrons’ speed. As a result, electron pairs and what appeared to be Majorana quasiparticles in some locations emerged. One can always observe the flow of the individual quasiparticles by deflecting one away.
The researchers do note that their detection of Majorana particles was not exact. They observed what Stanford physics professor Giorgio Gratta described as “basically excitations in a material,” as opposed to Majorana particles.
Confoundingly, it’s also uncertain if these particles could actually form spontaneously. Although it’s highly unlikely that they will occur in the cosmos, who are we to say? insert Gratta. They think they have found a particular type of Majorana quasiparticle, called a “chiral” fermion, which only moves in one direction on a one-dimensional path.
The researchers refer to the Majorana particle data as “smoking gun” proof. It has already been proposed that neutrinos could be their own antiparticles, though independent research is still needed to confirm this.
“Our team anticipated precisely where to locate the Majorana fermion and what to look for as its smoking gun’ experimental signature,” says senior author Shoucheng Zhan, a professor at Stanford. With this discovery, an incredibly thorough search spanning exactly eight decades in basic physics has been effectively wrapped up.
