Ultra-high energy neutrino detected by KM3NeT

JoeRobe writes: Scientists associated with the Kilometer Cube Neutrino Telescope, or KM3NeT, have reported detection of an ultra-high energy neutrino deep in the Mediterranean sea. The neutrino reportedly had an energy of 120 million billion electron volts (1.2x10^17 eV, or 120 PeV). This is similar to the energy of ping-pong ball travelling ~5 m/s, but all that energy was packed into a single subatomic particle. According to the New York Times, "Here, squeezed into one of the tiniest flecks of matter in our universe, that energy amounted to tens of thousands of times more than what can be achieved by the world’s premier particle accelerator, the Large Hadron Collider at CERN."

According to the authors of the Nature paper, the direction of the neutrino "is compatible with the extension of the galactic interstellar medium", but they did not find any catalogued source that would produce such a high energy neutrino, within the Milky Way or from about 40 other galaxies that could be candidates.

Phys.org describes the impressive scale of the KM3NeT detector array:

"It is located at 3,450 m depth, about 80 km from the coast of Portopalo di Capo Passero, Sicily. Its 700 m high detection units (DUs) are anchored to the seabed and positioned about 100 m apart.

Every DU is equipped with 18 Digital Optical Modules (DOM) each containing 31 photomultipliers (PMTs). In its final configuration, ARCA will comprise 230 DUs. The data collected are transmitted via a submarine cable to the shore station at the INFN Laboratori Nazionali del Sud."