Neutrinos are their own anti-particle

Subject : Science and technology

Section : Space technology

Concept :

An experiment in Japan recently reported that it failed to find “strong evidence” that the neutrinos are their own anti-particles.

Anti particles

Every elementary particle has an anti-particle. If the two meet, they will destroy each other in a flash of energy.
The electron’s anti-particle is the positron. They can be distinguished because they have opposite charges.
Similarly, neutrinos have anti-neutrinos. However, neither is electrically charged, nor possesses any other properties to really differentiate between them.

Experiment

Physicists working with the Kamioka Liquid Scintillator Antineutrino Detector (KamLAND) in Japan recently reported that after analysing two years’ data, they could not find signs that neutrinos could be their own anti-particles.
KamLAND looks for an event called neutrinoless double beta-decay.
In normal double beta-decay, two neutrons in an atom turn into two protons by emitting two electrons and two anti-neutrinos.
In neutrinoless double beta-decay, the anti-neutrinos aren’t emitted, which can happen only if anti-neutrinos are just different kinds of neutrinos.
This may rule out a few theories trying to explain neutrinos’ many mysterious properties.

What are neutrinos?

Neutrinos are the second most abundant particles in the world, after photons, or the light particle.
Neutrinos are mysterious particles, produced copiously in nuclear reactions in the Sun, stars, and elsewhere.
They also “oscillate”– meaning that different types of neutrinos change into one another.
Probing of oscillations of neutrinos and their relations with mass are crucial in studying the origin of the universe.
Neutrinos are created by various radioactive decays; during a supernova, by cosmic rays striking atoms etc.

Features of neutrinos:

Neutrinos interact very weakly with everything else – trillions of them pass through every human being every second without anyone noticing.
A neutrino’s spin always points in the opposite direction of its motion.
It is now generally believed that the phenomenon of neutrino oscillations require neutrinos to have tiny masses.