Signs of Neutrinos detected by Physicists

The multinational Forward Search Experiment team, lead by physicists from the University of California, Irvine, has made the first-ever detection of neutrino candidates produced by the CERN facility near Geneva, Switzerland’s Large Hadron Collider. The researchers describe how they witnessed six neutrino interactions during a pilot run of a compact emulsion detector built at the LHC in 2018 in an article published today in the journal Physical Review D.

“No indication of Neutrinos had ever been found at a particle collider before this experiment,” said co-author Jonathan Feng, UCI Distinguished Professor of physics and astronomy and FASER Collaboration co-leader. “This remarkable achievement is a step toward a better understanding of these elusive particles and their significance in the universe.”

According to him, the discovery made during the pilot provided his team with two critical pieces of information. Lead and tungsten plates alternated with layers of emulsion in the pilot instrument. Some of the Neutrinos created at the LHC collide with nuclei in dense metals, resulting in particles that pass through the emulsion layers and leave markings that are visible after processing.

These etchings reveal the particles’ energy, flavours (tau, muon, or electron), and whether they are Neutrinos or antineutrinos. The emulsion, according to Feng, works in a similar way to photography in the pre-digital camera period. Photons leave tracks on 35-millimeter film when exposed to light, which are revealed as patterns after the film is developed. After removing and developing the detector’s emulsion layers, the FASER researchers were able to see neutrino interactions as well.