Tau antineutrino
Composition :
Statistics :
Generation :
Family :
Interaction forces :
Symbol :
Antiparticle :
Mass :
Decays into :
Electric charge :
Color charge
Spin :
Weak isospin :
Weak hypercharge :
Chirality :
Elementary particle
Fermionic
Third
Lepton
weak,
gravity
ντ
Tau neutrino ( ντ )
Very small but non-zero (1)
0 e
none
¹/₂
¹/₂
-1
left-handed
_
TAU ANTINEUTRINO
General Characteristics
The tau antineutrino is a fundamental particle in the Standard Model of particle physics.
Fundamental Particle: The tau antineutrino is one of the elementary particles in the Standard Model, belonging to the family of leptons. It is the antiparticle counterpart of the tau neutrino (ντ).
Lepton Flavor: The tau antineutrino is associated with the tau lepton, which is the heaviest of the three charged leptons in the Standard Model. It participates in weak interactions mediated by the weak force, alongside other leptons and quarks.
Electrical Charge: The tau antineutrino has zero electrical charge, as do all neutrinos and antineutrinos. This property makes them electrically neutral, allowing them to interact solely through the weak force and gravity.
Spin: The tau antineutrino is a fermion, meaning it has a half-integer spin of 1/2 ħ, where ħ is the reduced Planck constant. This property categorizes it as a type of matter particle according to the spin-statistics theorem.
Mass: Neutrinos, including the tau antineutrino, were long believed to be massless according to the Standard Model. However, neutrino oscillation experiments have established that neutrinos have extremely small but nonzero masses. The exact mass of the tau antineutrino is not precisely determined but is inferred to be tiny compared to other fundamental particles.
Interaction: Tau antineutrinos primarily interact through the weak nuclear force, which is responsible for processes like beta decay and neutrino scattering. Because they interact so weakly, they can traverse matter over vast distances without being significantly absorbed or deflected.
Flavor Oscillation: Neutrinos and antineutrinos can change between different flavors (electron, muon, tau) as they propagate through space, a phenomenon known as neutrino oscillation. This implies that a tau antineutrino produced in a certain flavor state may evolve into a mixture of different flavor states over time.
Experimental Detection: Detecting tau antineutrinos is challenging due to their weak interactions and extremely low mass. Large-scale detectors, such as neutrino observatories and detectors placed near nuclear reactors or particle accelerators, are employed to capture rare interactions of neutrinos and antineutrinos with matter.
Creation of Tau Antineutrinos
Tau antineutrinos are created through various processes in particle interactions and astrophysical phenomena. Here are some of the key processes where tau antineutrinos are generated:
Electron-Positron annihilation: The electron-positron annihilation can finally lead to the production of a tau antineutrino.
Nuclear Reactions: In astrophysical environments such as the core of the Sun, nuclear reactions occur that produce a plethora of particles, including tau antineutrinos. For example, in the proton-proton chain reaction that powers the Sun, several steps involve the production of electron neutrinos electron antineutrinos and also muon and tau neutrinos and antineutrinos, including .
Particle Collisions: In high-energy particle collisions, such as those produced in particle accelerators like the Large Hadron Collider (LHC), tau antineutrinos can be generated as secondary particles. When particles collide with high energies, they can produce a variety of particles, including tau leptons and their corresponding neutrinos and antineutrinos.
Supernovae Explosions: During the catastrophic collapse and subsequent explosion of a massive star in a supernova event, enormous amounts of energy are released. Neutrinos of all flavors, including tau antineutrinos, are produced abundantly in this process. These neutrinos play a crucial role in carrying away a significant fraction of the gravitational energy released during the supernova explosion.
Tau antineutrino decay
See the inverse of the tau neutrino decay.
Figure 290 - Electron-Positron annihilation producing tau antineutrino
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