Researchers detect particles in Antarctica that do not fit the Standard Model

Detected by a sensor attached to a high-altitude balloon hovering over Antarctica

Researchers at Penn State University have found new evidence that suggests some particles detected in Antarctica do not fit the Standard Model.

The Standard Model refers to particle physics and is the theory describing three of the four known fundamental forces (the electromagnetic, weak and strong interactions, and not including gravitational force) in the universe.

It was developed in stages through the latter half of the 20th century, via the work of many scientists around the world, with the current formulation being finalised in the mid-1970s upon experimental confirmation of the existence of quarks. The Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.

However, the Penn State University boffins have written a paper outlining their arguments against this, thanks to their findings in Antarctica.

The researchers made their discovery while studying cosmic rays.

Cosmic rays are high-energy radiation, mainly originating outside the Solar System and even from distant galaxies. They are made up of low and high energy particles, and upon impact with the Earth's atmosphere, they can produce showers of secondary particles that sometimes reach the surface.

When low energy cosmic particles encounter the Earth, they usually pass right through; but high energy particles always run into something else, preventing them from passing through in one piece. When they do this, they cause an avalanche of collisions, creating a shower of particles that eventually emerge on the other side of the planet.

But while studying in Antarctica, what the scientists have found is proof that sometimes high-energy particle can make it all the way through without creating a particle shower, which could suggest that a particle exists that is not described by the Standard Model.

They uncovered two odd particle events using a sensor attached to a high-altitude balloon hovering over Antarctica, as part of a project called the Antarctic Impulsive Transient Antenna (ANITA).

The first ever such detection was back in 2006, with the second in 2014, and both indicated that a high-energy particle had somehow made its way through the planet without encountering anything.

However, the most recent experiment suggests they have found other evidence of the same type of particle, meaning two anomalies might represent unknown particles and thus result in sensors showing three events where unexplained properties had occurred.

The new evidence came in the form of sensor data from the IceCube experiment in which sensors buried in the Antarctic ice continually detect particle events.