Neutrinos

Neutrinos Latest News

The AMoRE experiment in South Korea has reported no evidence of neutrinoless double beta decay (0νββ)

About Neutrinos

• Neutrinos are nearly massless, electrically neutral subatomic particles that interact extremely weakly with matter.
• They belong to the lepton family, which is not subject to the strong nuclear force.
• Sources: Neutrinos are produced in radioactive decay, supernova explosions, nuclear fusion in the Sun, and cosmic ray interactions.
• Abundance: They are the second most abundant subatomic particle in the universe after photons. Every second, 100 trillion neutrinos pass harmlessly through the human body.
• Challenges in Detection: Due to their weak interaction with matter, detecting neutrinos requires highly sensitive detectors and long observation times.

What are Antiparticles?

• Every elementary particle has a corresponding antiparticle.
• When a particle meets its antiparticle, they annihilate, releasing energy.
• Example:
  • The electron's antiparticle is the positron (same mass, opposite charge).
  • Neutrinos have anti-neutrinos, but since they lack an electric charge, it is difficult to distinguish them.

Neutrinos and the Majorana Hypothesis

• Majorana Particles: Most subatomic particles have distinct anti-particles (e.g., the electron’s anti-particle is a positron). However, Majorana particles are their anti-particles.
• If neutrinos are found to be Majorana particles, it would have profound implications for particle physics and could explain why the universe has more matter than antimatter.

What is Double Beta Decay?

• Beta Decay: A process where an unstable atomic nucleus converts a neutron into a proton, emitting an electron and an anti-neutrino.
• Double Beta Decay (2νββ): A rare nuclear decay where two neutrons transform into two protons, emitting two electrons and two anti-neutrinos. This process has been observed in certain isotopes.
• Neutrinoless Double Beta Decay (0νββ): A hypothetical decay where only two electrons are emitted, and no neutrinos.
  • This could only happen if neutrinos and anti-neutrinos are the same particle (Majorana particles).
  • If 0νββ is observed, it could also help determine the absolute mass of neutrinos.

AMoRE Experiment and Its Findings

• Location: South Korea.
• Method: The experiment observed 3 kg of molybdenum-100 (Mo-100), a nucleus known to undergo double beta decay.
• Temperature: The detectors were cooled to fractions above absolute zero to detect tiny energy changes.
• Result: No evidence of 0νββ was found, but scientists set an upper limit:
  • If 0νββ exists, Mo-100 nuclei would decay through this process in at least 10²⁴ years (a trillion times longer than the age of the universe).
  • The neutrino mass is estimated to be below 0.22-0.65 billionths of a proton’s mass, but not necessarily zero.

Neutrinos FAQs

Q1. What are neutrinos?
Ans. Neutrinos are nearly massless, electrically neutral subatomic particles that interact weakly with matter.

Q2. Why are neutrinos important in physics?
Ans. Neutrinos help scientists understand the fundamental forces of nature, dark matter, and the universe's evolution.

Q3. What is the Indian Neutrino Observatory (INO)?
Ans. INO is a proposed underground research facility in Tamil Nadu to study neutrinos, which faces environmental concerns.

Q4. What are the challenges in detecting neutrinos?
Ans. Neutrinos rarely interact with matter, requiring massive underground detectors like Super-Kamiokande in Japan.

Source: TH