Electron neutrinos were first observed experimentally in a recent experiment by physicists at the European Organization for Nuclear Research (CERN) producing proton-proton collisions at the facility’s Large Hadron Collider (LHC).
Neutrinos are neutral elementary particles with almost no mass. They were first detected in 1956, and like all fermions, they have an integral spin of 1/2 and rarely interact with ordinary matter outside of the weak force.
There are three different types of neutrinos: electrons, muons, and tau particles. Due to their weak interactions with matter, all three types of neutrinos are considered to be among the most elusive particles in the universe. Nevertheless, physicists have had some success with experiments studying the properties of neutrinos, as they are produced by astrophysical sources such as supernovae and the Sun.
On Earth, artificial sources such as nuclear reactors also produce neutrinos, and they have been successfully detected in past fixed target experiments. Last year’s experimentMuon neutrinos produced during proton-proton collisions have been detected directly in a particle accelerator by the Forward Search Experiment (FASER) at the Large Hadron Collision at CERN.
Following last year’s successful detection, the FASER collaboration has reported another success: the detection of another of the three mysterious and elusive neutrino types.
According to the new discovery, electron neutrinos were experimentally detected using a special tungsten detector placed 500 metres away from the source of protons orbiting around the LHC collider.
Electron neutrinos are detected when they escape the proton collision stream and interact with tungsten atoms, resulting in the production of highly energetic electrons and other particles, and researchers from the FASER collaboration were able to detect the arrival of an electron neutrino in a tungsten detector due to the specific effect of a secondary electron-positron pair and the presence of a photon accompanying the traveling “daughter” electron.
Under these circumstances, researchers at CERN report detecting four electron neutrinos in a recent experiment. Based on their observations, it seems highly unlikely that the particle tracks recorded in the detector were produced by other electrically neutral particles that could be mistaken for neutrinos.
“This is the first measurement of the neutrino interaction cross section in these energy ranges,” the researchers detailed in their recently published study. They expressed confidence that the chance that the detected signal was the result of chance is close to 0.00003%.
Going forward, the researchers hope that this successful particle detection will lead to further success in the ability to detect and distinguish between different types of neutrinos during experimental observations.
Ultimately, ongoing experiments like these will enable physicists to expand their overall understanding of electroweak interactions and conduct future studies of the proton’s internal dynamics and neutrinos, including their quark-gluon structure.
Recent FASER collaborations study A paper by R.M. Abraham and colleagues titled “First measurement of 𝜈e𝜈𝑒 and 𝜈𝜇𝜈𝜇 interaction cross sections at the LHC with the FASER emulsion detector” was recently published in the journal. Physics Review Letters.
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