CERN has given the green light to a new experiment, in the hope of detecting a hypothetical particle that could potentially explain why the universe is made of matter instead of antimatter.
The experiment is called SHiP (Search for Hidden Particles), and it willl be installed at CERN by 2026, with an expected cost of about $200 million (£140 million). But before construction of the instrument can begin, each member state needs to approve the project.
SHiP will look for sterile neutrinos, a hypothetical particle that interacts extremely weakly, if at all, with the ordinary matter we are made of. So far we have detected three types, or “flavors,” of neutrinos: electron, muon, and tau neutrinos. While the different flavors have different properties, the neutrinos are able to change from one to the other, a phenomenon called oscillation.
Sterile neutrinos could be produced by this kind of oscillation. The sterile neutrinos that are going to be hunted at CERN belong to a specific group called Heavy Neutral Leptons. They are significantly more massive than the flavored variety and, unlike their lighter counterpart, could give us clues to the dominance of matter over antimatter in the universe.
The Standard Model of particle physics is the theory that connects three of the four fundamental forces (electromagnetism, strong nuclear force, and weak nuclear force) and fundamental particles. It predicted the existence of the top quark, tau neutrino, and Higgs boson before they were detected. In the Standard Model, neutrinos are massless, but since it was devised, we have discovered they do have mass (albeit very small). This implies that the Standard Model is limited and there’s yet more physics to uncover.
"Finding a light sterile neutrino would be a Nobel prize discovery, but it wouldn't solve the problems of the Standard Model," Andrey Golutvin, a SHiP spokeperson, said to Physics World.
In the new experiment, high-intensity proton beams produced by CERN’s Super Proton Synchrotron will be shot at a new tungsten-molybdenum target, which will generate a cascade of particles containing charm quarks. These quarks decay into active neutrinos, which might then oscillate into heavy sterile neutrinos.
Sterile neutrinos are not only interesting from a particle physics point of view, but from an astrophysical one as well. If they are proven to exist, they could be the particles that dark matter is made of, and they might also be responsible for several events in the moments after the Big Bang.
[H/T: Physics World]
