[Physics Class Notes] on Neutrino Pdf for Exam

The neutrino can be defined as an elementary subatomic particle with no charge and 1/2 unit spin. These fermions then react because of weak interaction and gravity. The rest mass of a Neutrino is almost negligible hence considered to be zero. The rest mass of a neutrino is comparatively very small than the elementary particles. Wolfgang Pauli discovered Neutrino in 1930, and the name was popularized in Science by the Italian Physicist Enrico Fermi. In Italians, The Neutrinos means “the little neutral ones” are electrically neutral particles, and their size is smaller than that of Neutrons. 

Properties and Types of Neutrino

Some of the most prominent properties of Neutrino are:

• These Neutrinos belong to the family of leptons, this particle family has weak interactive forces. 

• The Neutrino is of three basic kinds depending upon the charged lepton that they are associated with. These charged leptons are the electron, the muon, and the tau respectively. These associated electrons are named electron-neutrino, muon-neutrino, and tau-neutrino. 

• A neutrino also has an antimatter component that is known as an antineutrino. The Neutrino and antineutrino together comprise a hot area of research in modern physics with many scientists and experts working in this field.

• Neutrinos are not affected by the electromagnetic forces and hence, do not cause the ionization of matter. 

• These Neutrinos react with matter only through extremely weak interactive forces.

• They are also capable of passing through an enormous number of atoms without causing any reaction and hence these are the most penetrating subatomic particles.

• The Neutrinos can also change a nucleus into another and this process is used in a radiochemical neutrino detector.

Neutrinos are found in various types in space. These types are:

As mentioned earlier, neutrinos are of three types or flavours and each of them has its respective properties. The first discovered neutrino is the electron-neutrino. Electron-neutrino has no electric charge and mass. It was discovered by Wolfgang Pauli to satisfy the energy loss in the process of radioactive beta decay. This particle is emitted along with a positron in positive beta decay. For negative beta decay, an electron with its antimatter particle that is an antineutrino is emitted.

Post the discovery of the second charge lepton, the muon, eventual identification of the second type of neutrino, the muon-neutrino started. Based on the results of a particle-accelerator experiment, high energy muon-neutrinos were discovered in 1962. They were produced from the decay of pi-meson. Though usually unreactive like other neutrinos, sometimes muon-neutrino reacts with protons and neutrons to produce muons.

In 2000, physicists experimentally showed the first evidence of the existence of the tau-neutrino. It was after the discovery of the tau leptons.

There are many active research areas involving neutrinos. Neutrino properties, testing predictions of their behaviour, and masses and rates of CP violation which is still unpredicted from the current theories. These subatomic particles are indispensable for the validation of the law of conservation of energy. They are related to radioactivity and play a very important role in nuclear physics. Knowledge of neutrinos and their properties enable physicists to understand the dynamics of several nuclear reactions.