Neutrinos shatter records as they tear through the Mediterranean Ocean

The incredibly powerful neutrinos that tore through a new Mediterranean particle detector have amazed physicists, offering a first glimpse into some of the universe’s most intense events, such as the collision of ultrafine black holes.

Neutrinos, sometimes known as “ghost particles,” interact minimally with matter due to their small mass and lack of charge. By placing detectors in dense mediums like water or ice, researchers hope to detect the subtle signals of neutrinos interacting with atoms and producing showers of particles. This, in turn, helps in understanding their properties.

Damian Dornick from the Centre for Particle Physics in Marseille, France, along with his team, discovered the most energetic neutrino ever recorded. Using the Cubic Kilometer Neutrino Telescope (km3net) at the bottom of the Mediterranean Sea, they detected this extraordinary neutrino on February 13, 2023. The discovery left the researchers astonished.

“Initially, we were puzzled,” he says. “As we delved deeper, we realized that this event was truly exceptional, and our excitement grew.”

The signal observed appeared as a bright, almost horizontal line on the detector, believed to be created by muons – small electron-like particles produced by neutrinos interacting with km3net’s detectors.

https://www.youtube.com/watch?v=gpuargix2u4

When the researchers tentatively published their results in 2024, they were still in the process of calculating the exact energy of the particles. “The high energy levels surprised us, as our neutrino simulations had not yet reached such levels,” says Morgan Wasco from Oxford University.

To validate their findings, researchers meticulously considered the impact of other sources of illumination on the detector, such as neutrinos generated by cosmic rays – charged particles from space. These signals are believed to surpass higher-energy neutrinos originating from more distant cosmic sources by 1 to 100 million times.

The energy of the detected neutrino was calculated to be 120 peta electron volts (PEV), about 10 times higher than the previous record set by the IceCube neutrino observatory in Antarctica. Such high-energy neutrino detections offer unique insights into the events producing them, like black hole mergers and supernova explosions.

“While cosmic rays get deflected and lose their original direction as they pass through interstellar space, neutrinos travel straight,” explains Wascko. The relatively large spatial spread of the neutrino’s trail in this case makes pinpointing the exact source challenging, but future enhancements to the telescope could potentially identify similarly powerful neutrinos and their sources.