Sterile Neutrinos Unlocking Secrets

The neutrino is perhaps the most fascinating inhabitant of the subatomic world. Nearly massless, this fundamental particle experiences only the weak nuclear force and the much fainter force of gravity. With no more than these feeble connections to other forms of matter, a neutrino can pass through the entire Earth with just a tiny chance of hitting an atom. Ghosts, who are said to be able to pass through walls, have nothing on neutrinos.

The neutrinos’ phantom properties are not the only thing that sets them apart from other fundamental particles. They are unique in that they don’t have a fixed identity. The three known forms of neutrinos are able to transform into one another through a cyclical process called neutrino oscillation. In addition to being subatomic specters, they are also quantum chameleons.  READ MORE...

World's Largest Underwater Telescope in China

Scientists in China are building the world's largest "ghost particle" detector 11,500 feet (3,500 meters) beneath the surface of the ocean.

The Tropical Deep-sea Neutrino Telescope (TRIDENT) — called Hai ling or "Ocean Bell" in Chinese — will be anchored to the seabed of the Western Pacific Ocean. Upon completion in 2030, it will scan for rare flashes of light made by elusive particles as they briefly become tangible in the ocean depths.

Every second, about 100 billion ghost particles, called neutrinos, pass through each square centimeter of your body. And yet, true to their spooky nickname, neutrinos' nonexistent electrical charge and almost-zero mass mean they barely interact with other types of matter.

But by slowing neutrinos down, physicists can trace some of the particles' origins billions of light-years away to ancient, cataclysmic stellar explosions and galactic collisions.

That's where the ocean bell comes in.

"Using Earth as a shield, TRIDENT will detect neutrinos penetrating from the opposite side of the planet," Xu Donglian, the project's chief scientist, told journalists at a news conference Oct. 10. "As TRIDENT is near the equator, it can receive neutrinos coming from all directions with the rotation of the Earth, enabling all-sky observation without any blind spots."

Neutrinos are everywhere — they are second only to photons as the most abundant subatomic particles in the universe and are produced in the nuclear fire of stars, in enormous supernova explosions, in cosmic rays and radioactive decay, and in particle accelerators and nuclear reactors on Earth..

Despite their ubiquity, their minimal interactions with other matter make neutrinos incredibly difficult to detect. They were first discovered zipping out of a nuclear reactor in 1956, and many neutrino-detection experiments have spotted the steady bombardment of the particles sent to us from the sun; but this cascade masks rarer neutrinos produced when cosmic rays, whose sources remain mysterious, strike Earth's atmosphere.  READ MORE...

Neutrinos and Dark Matter

PNNL chemist Isaac Arnquist examines ultra-low radiation copper cables specially created for sensitive physics detection experiments. Credit: Andrea Starr, Pacific Northwest National Laboratory



Ultra-low radiation cables reduce background noise for neutrino and dark matter detectors.

Imagine trying to tune a radio to a single station but instead encountering static noise and interfering signals from your own equipment. That is the challenge facing research teams searching for evidence of extremely rare events that could help understand the origin and nature of matter in the universe. 

It turns out that when you are trying to tune into some of the universe’s weakest signals, it helps to make your instruments very quiet.

Around the world, more than a dozen teams are listening for the pops and electronic sizzle that might mean they have finally tuned into the right channel. These scientists and engineers have gone to extraordinary lengths to shield their experiments from false signals created by cosmic radiation. 

Most such experiments are found in very inaccessible places—such as a mile underground in a nickel mine in Sudbury, Ontario, Canada, or in an abandoned gold mine in Lead, South Dakota—to shield them from naturally radioactive elements on Earth. 

However, one such source of fake signals comes from natural radioactivity in the very electronics that are designed to record potential signals.

Ultra-low radiation cables reduce background noise for neutrino and dark matter detectors.

Imagine trying to tune a radio to a single station but instead encountering static noise and interfering signals from your own equipment. That is the challenge facing research teams searching for evidence of extremely rare events that could help understand the origin and nature of matter in the universe. 

It turns out that when you are trying to tune into some of the universe’s weakest signals, it helps to make your instruments very quiet.

Around the world, more than a dozen teams are listening for the pops and electronic sizzle that might mean they have finally tuned into the right channel. These scientists and engineers have gone to extraordinary lengths to shield their experiments from false signals created by cosmic radiation. 

Most such experiments are found in very inaccessible places—such as a mile underground in a nickel mine in Sudbury, Ontario, Canada, or in an abandoned gold mine in Lead, South Dakota—to shield them from naturally radioactive elements on Earth. 

However, one such source of fake signals comes from natural radioactivity in the very electronics that are designed to record potential signals.  READ MORE...