Scientists at the NOvA (NuMI Off-axis 𝜈e Appearance) collaboration in Minnesota, U.S., are conducting advanced research on neutrinos. Their latest data acquisition sheds light on neutrino mass and their significance in cosmic evolution.
Neutrinos/Ghost Particle
- About: Neutrinos are a type of subatomic particle.
Historical Context of Neutrinos
- First Detection: Neutrinos were first detected from a supernova explosion in 1987, with detections made three hours before the light from the explosion reached Earth.
- This marked the beginning of neutrino astronomy.
- Mass Assumption: For nearly 50 years, physicists assumed neutrinos were massless like photons.
- This assumption was based on the idea that massive particles cannot travel at the speed of light.
Breakthroughs in Neutrino Research
- Discovery of Mass: In the late 1990s, evidence from Japan and Canada showed that neutrinos have mass because they can change from one type to another as they travel, which massless particles cannot do.
- Standard Model Update: The discovery of neutrino mass challenges the Standard Model of particle physics, which does not initially predict massive neutrinos.
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- They don’t have an electric charge, have a small mass, and are left-handed (a physics term meaning the direction of its spin is opposite to the direction of its motion).
- Reason for them to be called Ghost Particles: The rarity of interactions with other particles makes them almost impossible to track.
- That’s why they’re called ghost particles — the vast majority skirt around undetected.Abundance of Neutrinos: They are the second-most abundant particles after photons (particles of light) and the most abundant among particles that make up matter.
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- Production and Sources of Neutrinos: Neutrinos are generally produced when leptons interact with matter.
- It can be obtained from both natural (Cosmological neutrinos (the Big-bang), etc.) and man-made (Reactor neutrinos (during fission), etc.) sources.
- Types/Flavours: Neutrinos come in three types or “flavours” – electron neutrino, tau neutrino and muon neutrino.
- Neutrino Oscillation: They can change from one flavour to another as they travel. This process is called neutrino oscillation and is an unusual quantum phenomenon.
- Example: Neutrinos from the Sun are initially electron-neutrinos, but on Earth, many of them are detected as muon-neutrinos.
- Observation: Neutrinos’ weak charge and almost nonexistent mass have made them notoriously difficult for scientists to observe.
- They can only be “seen” when they interact with other particles.
- Neutrino Detection Methods
- Physicists have constructed detectors with very fine tracking capabilities to study neutrinos.
- These detectors are also designed to be large to maximise the number of interactions between neutrinos and the detector’s matter.
NOvA Overview
- Acronym: NOvA stands for ‘NuMI Off-axis νe Appearance’.
- Location: It is located in Minnesota, United States.
- Function: NOvA creates a beam of neutrinos.
- Detection: The neutrino beam travels 800 km to a 14,000-tonne detector.
- Management: NOvA is managed by the Fermi National Accelerator Laboratory.
- Fermi National Accelerator Laboratory (Fermilab), is a United States Department of Energy national laboratory specialising in high-energy particle physics.
Goals and Findings of NOvA
- Cosmic Evolution: NOvA is designed to determine the role of neutrinos in the evolution of the cosmos.
- Neutrino Mass: It aims to understand which type of neutrino has the most mass and which has the least.
- Mass Mechanism: This is crucial because neutrinos may acquire their mass through a different mechanism than other matter particles.
- Physics Questions: Unravelling this could answer many open questions in physics.
- Key Findings: Neutrinos come in three varieties: muon, electron, and tau. Recent results from the NOvA experiment suggest that among these, there are two lighter neutrinos and one heavier neutrino.
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Significance of Studying Neutrinos
- Better Understanding of the Universe: Understanding neutrinos helps us unravel the mysteries of the universe’s formation and its current state.
- Information Carriers: Neutrinos can travel through most matter without interaction, allowing them to carry information across vast distances.
- While electromagnetic waves are commonly used for transmitting information, they are not always effective in all situations.
- Neutrinos can provide critical data where electromagnetic waves may fall short.
- Example: Seawater is opaque to electromagnetic radiation of shorter wavelength, which impedes the transmission of waves of certain frequencies to submarines. Neutrinos on the other hand can easily pass through 1,000 light years (9,400 million million km) of lead, so an ocean will hardly be a barrier.
Experiments involving Neutrino Universe and India Neutrino Project (INO):
- Key Neutrino Experiments
- Super-K III: Located in Japan.
- Sudbury Neutrino Observatory (SNO+): Based in Canada.
- MiniBOONE and MicroBOONE: Based in the U.S.
- Double CHOOZ: Situated in France.
- Jiangmen Underground Neutrino Observatory (JUNO): Located in China.
- OPERA: Conducted in Switzerland.
- IceCube Neutrino Observatory: It is the world’s largest neutrino telescope located in Antarctica.
- India’s Neutrino Project
- India-based Neutrino Observatory (INO): Planned for Tamil Nadu, India.
- Location: The INO collaboration has decided on a site in the Bodi West Hills (BWH) region in the Theni district of Tamil Nadu.
- Funding and Support: Funded by the Department of Atomic Energy.
- Current Status: Faces an uncertain future due to procedural issues and lack of political support.
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July 23, 2024