NEUTRINOS - SCIENCE AND TECHNOLOGY
News: Are
neutrinos their own anti-particles?
What's in the news?
● Neutrinos are the second
most abundant particles in the cosmos.
Because they are so ubiquitous, their properties have an important influence on
the structure of the universe.
● An
open question about neutrinos is whether they are their own anti-particles. An
experiment in Japan recently reported that it failed to find “strong evidence”
that this is so, ruling out a few theories trying to explain neutrinos’ many
mysterious properties.
Key takeaways:
● 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.
Anti-neutrinos:
● Neutrinos
have anti-neutrinos like electrons having their anti-particle as positrons.
● However,
neither is electrically charged, nor possesses any other properties to really
differentiate between them.
Lack of evidence:
● But
physicists working with the Kamioka Liquid Scintillator Antineutrino Detector
(KamLAND) in Japan recently reported that after analyzing two years of 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.
Go back to basics:
Neutrinos:
● Neutrinos
are fundamental particles that are similar to electrons but have no electric charge.
● They
are one of the most abundant particles in the universe, but they are also one
of the most difficult to detect because they interact only very weakly with matter.
● The
neutrino has a very little mass and a
spin ½.
Origin:
● Neutrinos
are created in a variety of natural
processes, including
○ 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.
● They
are also produced in particle accelerators and nuclear reactors.
Types of Neutrinos:
● There
are three types of neutrinos such as
○ Electron
neutrino (associated with the electron)
○ Muon
neutrino
○ Tau
neutrino