Neutrino Particle

A Neutrino Particle is a fermion particle that interacts only via the weak interaction and gravity.

• Context:
  • It can (typically) follow Fermi–Dirac statistics, similar to other fermions.
  • It can (often) be electrically neutral, possessing no electric charge.
  • It can have a very small rest mass, significantly less than that of other elementary particles.
  • It can pass through normal matter unimpeded due to its lack of interaction with electromagnetic and strong interactions.
  • It can oscillate between different flavors (such as electron neutrino, muon neutrino, and tau neutrino) in a phenomenon known as neutrino oscillation.
  • It can be associated with specific charged leptons corresponding to its flavor.
  • It can possess an antiparticle counterpart, the antineutrino, which has opposite lepton number and chirality.
  • It can be created in various radioactive decay processes, including beta decay, natural and artificial nuclear reactions, and during events like supernovas and neutron star spin-downs.
  • It can be detected through the flux of solar neutrinos, with about 65 billion per second per square centimeter at the Earth's surface.
  • It can be used for tomography of the Earth's interior due to its ability to pass through dense materials.
  • ...
• Example(s):
  • Electron Neutrino that showcases a neutrino flavor associated with the electron.
  • Muon Neutrino that demonstrates a neutrino flavor associated with the muon.
  • Tau Neutrino that highlights a neutrino flavor associated with the tau particle.
  • ...
• Counter-Example(s):
  • Photons, which interact via the electromagnetic interaction.
  • Protons, which interact via the strong interaction and have a significant rest mass.
• See: Tomography, Bubble Chamber, Argonne National Laboratory, Elementary Particle, Lepton, Fermionic, Weak Interaction, Gravitation, Chirality (Physics), Weak Isospin, Lepton Number, Flavour (Particle Physics).

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References

2024

• (Wikipedia, 2024) ⇒ https://en.wikipedia.org/wiki/neutrino Retrieved:2024-6-9.
  • A neutrino (; denoted by the Greek letter ν) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The rest mass of the neutrino is much smaller than that of the other known elementary particles (excluding massless particles). The weak force has a very short range, the gravitational interaction is extremely weak due to the very small mass of the neutrino, and neutrinos do not participate in the electromagnetic interaction or the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected.

    Weak interactions create neutrinos in one of three leptonic flavors:

    1. electron neutrino,
    2. muon neutrino,
    3. tau neutrino,
  • Each flavor is associated with the correspondingly named charged lepton. Although neutrinos were long believed to be massless, it is now known that there are three discrete neutrino masses with different tiny values (the smallest of which could even be zero ), but the three masses do not uniquely correspond to the three flavors: A neutrino created with a specific flavor is a specific mixture of all three mass states (a quantum superposition). Similar to some other neutral particles, neutrinos oscillate between different flavors in flight as a consequence. For example, an electron neutrino produced in a beta decay reaction may interact in a distant detector as a muon or tau neutrino. The three mass values are not yet known as of 2024, but laboratory experiments and cosmological observations have determined the differences of their squares, an upper limit on their sum (< ), and an upper limit on the mass of the electron neutrino. For each neutrino, there also exists a corresponding antiparticle, called an antineutrino, which also has spin of and no electric charge. Antineutrinos are distinguished from neutrinos by having opposite-signed lepton number and weak isospin, and right-handed instead of left-handed chirality. To conserve total lepton number (in nuclear beta decay), electron neutrinos only appear together with positrons (anti-electrons) or electron-antineutrinos, whereas electron antineutrinos only appear with electrons or electron neutrinos. Neutrinos are created by various radioactive decays; the following list is not exhaustive, but includes some of those processes: * beta decay of atomic nuclei or hadrons * natural nuclear reactions such as those that take place in the core of a star
    • artificial nuclear reactions in nuclear reactors, nuclear bombs, or particle accelerators
    • during a supernova
    • during the spin-down of a neutron star
    • when cosmic rays or accelerated particle beams strike atoms
  • The majority of neutrinos which are detected about the Earth are from nuclear reactions inside the Sun. At the surface of the Earth, the flux is about 65 billion () solar neutrinos, per second per square centimeter. Neutrinos can be used for tomography of the interior of the Earth.

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