Physics of neutrinos
- Like the familiar photon and the electron, the neutrino is one of the known fundamental particles of nature.
- It is believed that a majority of the neutrinos in the universe were produced soon after the Big Bang about 14 billion years ago.
- And like the low energy (microwave) relic photons from the Big Bang that fill the universe, low energy (relic) neutrinos (with energies of about ten-thousandths of one electronvolt or eV) also form part of the cosmic background.
- As a consequence, neutrinos constitute the second most abundant particles in the universe after photons.
- Compared to the photon density of about 410 photons/cm³, the neutrino density is about 330 neutrinos/cm³.
Why INO ?
- Neutrinos are fundamental particles belonging to the lepton family. They come in three flavours, one associated with electrons and the others with their heavier cousins the muon and the Tau. According to standard model of particle physics, they are mass less
- Neutrino detectors around the world seem to see evidence that these weakly interacting, little-understood particles are not really massless, as was thought so far.
- Not only do they have non-zero masses, different species (or flavours ) of neutrinos seem to mix and oscillate into one another as they traverse through the cosmos.
- If this is true, this is not only one of the first pieces of evidence for physics beyond the so-called Standard Model of Particle Physics but would also have great impact on diverse fields such as nuclear and particle physics, astrophysics and cosmology.
- It is thus imperative to study the details of the interactions of these particles.
- The best option of course is to have a lab in order to do so.
- In order to maximize the sensitivity to the interactions of these weakly interacting particles, such a neutrino lab is necessarily placed underground.
- The India-based Neutrino Observatory (INO) Project is a multi-institutional effort aimed at building a world-class underground laboratory with a rock cover of approx.1200 m for non-accelerator based high energy and nuclear physics research in India.
- The project includes
- construction of an underground laboratory and associated surface facilities at Pottipuram in Bodi west hills of Theni District of Tamil Nadu,
- construction of a Iron Calorimeter (ICAL) detector for studying neutrinos,
- setting up of National Centre for High Energy Physics at Madurai, for the operation and maintenance of the underground laboratory, human resource development and detector R&D along with its applications.
- According to government INO will be the agent of transforming physics of this kind in India and will make a global impact. The outcome of this investment will be extraordinary and long term.
- Understanding the particle will help scientists pick the correct theory beyond the standard model of particle physics and address the problem of matter-antimatter asymmetry of the universe.
- Research on neutrino particle would be path breaking in the field of science and will help in knowing more about the universe.
- An important outcome of the project will be training young researchers in large-scale experimental science
o It can play a role in nuclear non-proliferation through the remote monitoring of nuclear reactors. Using Neutrino detectors, the plutonium content can be monitored remotely and can be used to detect any pilferage.
o Study of Geoneutrinos might help creating an earthquake warning system. This field of science is called Neutrino Tomography.
- This year’s Nobel Prize for Physics underscores the need to study the nature of neutrino, but imagined fears and unfounded allegations are thwarting Indian efforts in that direction.
- Since the beginning of the year, neutrino, has been in the national news for all the wrong reasons. Misinformed activists on one hand and political opportunists on the other have together managed to stall a major Indian initiative to build a world-class underground neutrino research laboratory by invoking baseless fears of harmful impacts of the project, including dangerous radioactive fallout, pollution of water bodies and geological impact on dams
- The project is held up following a public interest litigation (PIL) in the Madras High Court and a petition to the Southern bench of the National Green Tribunal
- Now neutrino is back in the news, not just national but international. But this time it is for the right reason. The Nobel Prize in Physics for this year has been awarded for the discovery of strange quantum mechanical properties of this mysterious particle. The discovery has helped resolve a four-decade-old problem in solar astronomy and has pointed to the incompleteness of the current theory of the fundamental constituents of matter and the forces of interaction among them, thus emphasising the importance of continued neutrino research for a fuller understanding of the nature of the universe.
- The 56-year-old Japanese physicist, Takaaki Kajita, and the 72-year-old Canadian physicist, Arthur B. McDonald, have been jointly awarded the 2015 Nobel Prize in physics “for the discovery of neutrino oscillations, which shows that neutrinos have mass”.