Sterile neutrinos: Physicists fail to find mysterious theoretical particle

After many years of trying, physicists aren’t any nearer to discovering theorised particles that might assist clear up ongoing issues in physics

By Leah Crane

The hunt for mysterious theoretical particles often known as sterile neutrinos has turned up empty once more. Neutrinos are extraordinarily gentle subatomic particles that hardly work together with common matter. There are three recognized varieties and the seek for a fourth has been happening for many years. Now, a brand new set of analyses has failed to search out any signal that it exists.

Sterile neutrinos get their identify as a result of, not like the opposite three varieties, they’d solely work together through gravity and never the opposite elementary forces. Many theoretical physicists discovered the thought of a sterile neutrino promising as a result of it had the potential to elucidate a number of anomalies present in particle physics experiments, in addition to being related to the thriller of darkish matter. However as a result of neutrinos are so small and work together so weakly with different matter, we will solely observe them not directly, through the merchandise of collisions with different particles.

Within the Nineties and early 2000s, two neutrino experiments discovered extra of those merchandise than anticipated. Nonetheless, neither of them was capable of inform the distinction between electrons and photons in its outcomes – and sterile neutrinos would solely produce further electrons, not photons. A more recent experiment referred to as MicroBooNE on the Fermi Nationwide Accelerator Laboratory in Illinois can inform the distinction, however its first three years of knowledge present no further neutrino merchandise in any respect.

“I might have actually anticipated to see an extra in both the photons or the electrons and we haven’t seen one in both, which opens up extra questions,” says MicroBooNE spokesperson Justin Evans on the College of Manchester within the UK. We nonetheless haven’t any technique to clarify the sooner outcomes, so they may level to extra unique bodily processes that haven’t but been thought of, he says.

So is the hunt for the sterile neutrino over? “We undoubtedly will not be seeing any proof for a sterile neutrino,” says Evans. “As as to whether it’s utterly lifeless, I feel that relies upon who you ask, however you’ve actually received to get much more creative to get a sterile neutrino into your particle physics fashions now.”

Signal as much as Misplaced in Area-Time, a free month-to-month publication on the weirdness of actuality