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NoVA

27th July, 2024

NoVA

Source: HINDU

Disclaimer: Copyright infringement not intended.

Context

  • Scientists presented the latest results from the NOvA collaboration at a conference in Italy on June 17.
  • They said the collaboration had acquired twice as much data as it had during NOvA’s previous run, four years ago.
  • The new results complemented the previous ones with greater precision.

Details

About Neutrinos

  • Nature of Neutrinos:
    • Subatomic particles with no electric charge.
    • Have a small mass and are left-handed (spin opposite to motion).
    • Second-most abundant particles in the universe after photons.
  • Production:
    • Produced when leptons (such as muons, electrons, and tauons) interact with matter.
    • Rarely interact with matter, making them difficult to study.

Neutrinos are... poster

https://www.iasgyan.in/daily-current-affairs/neutrinos-37

Importance of Studying Neutrinos

  • Technological Advancements: Neutrinos have the potential to revolutionize technology due to their unique properties.
  • Scientific Interest: Crucial for understanding fundamental physics and the universe’s evolution.
  • Communication:
    • Neutrinos can pass through most matter untouched, making them potential carriers of information across large distances.
    • Could revolutionize communication technologies, especially where electromagnetic waves are ineffective (e.g., underwater).

Challenges in Neutrino Detection

  • Low Interaction Rate: Neutrinos interact with matter very rarely (e.g., a muon-neutrino interacts with an atom’s nucleus once in a million times).
  • Large Detectors Required: Detectors need fine tracking capabilities and large volumes to maximize interactions.

NOvA Experiment Overview

  • Acronym: NuMI Off-axis νe Appearance (NuMI Off-axis Electron Neutrino Appearance).
  • Location: Minnesota, U.S and extends to northern Minnesota.
  • Managed by: Fermi National Accelerator Laboratory.
  • Setup: Creates a beam of neutrinos that travel 800 km to a 14,000-tonne detector.

Objectives of NOvA

  • Role of Neutrinos in Cosmic Evolution:
    • Determine which neutrino type has the most mass.
    • Understanding neutrino mass could answer fundamental physics questions.
  • Mechanism of Mass Acquisition: Neutrinos may gain mass through a different mechanism than other particles.
  • Explore CP Violation in the Lepton Sector: Investigate whether neutrinos and antineutrinos behave differently, which could explain the matter-antimatter asymmetry in the universe.

Neutrino vs. Antineutrino

Property

Neutrino

Antineutrino

Definition

Subatomic particle with no charge and half-integer spin

Antiparticle with no charge and half-integer spin

Lepton Number

Positive lepton number (+1)

Negative lepton number (-1)

Chirality

Left-handed helicity

Right-handed helicity

Weak Isospin

+1/2

-1/2

Interactions

Weak interaction and gravity

Weak interaction and gravity

Production

Produced in beta decay and other weak interactions

Produced in beta decay and other weak interactions

Detection

Produces negatively charged electrons upon interaction

Produces positively charged positrons upon interaction

Matter vs. Antimatter

Property

Matter

Antimatter

Definition

Composed of particles such as electrons, protons, and neutrons

Composed of antiparticles such as positrons, antiprotons, and antineutrons

Charge

Particles have positive or negative charge

Antiparticles have opposite charges to their corresponding particles

Mass

Positive mass

Positive mass (same as corresponding particles)

Spin

Half-integer spin

Half-integer spin (same as corresponding particles)

Interaction

Subject to electromagnetic, weak, and strong forces

Subject to electromagnetic, weak, and strong forces (opposite charges cause different interaction behavior)

Annihilation

When matter and antimatter collide, they annihilate, producing energy (photons)

When antimatter and matter collide, they annihilate, producing energy (photons)

Examples

Electrons, protons, neutrons

Positrons, antiprotons, antineutrons

Historical Context

  • Neutrino Astronomy:
    • Began with the detection of neutrinos from a supernova in 1987.
    • Neutrinos detected before the light from the explosion reached Earth.
  • Mass Discovery:
    • Initially thought to be massless like photons.
    • Evidence in the late 1990s from Japan and Canada showed neutrinos have mass and can oscillate between types.

The Neutrino Mass Hierarchy

  • Neutrino Oscillation: Neutrinos change types as they travel long distances.
  • Mass Hierarchy Models:
    • Normal Order: One type is much heavier, and the other two have lower comparable masses.
    • Inverted Order: One type is lighter, and the other two have higher comparable masses.

Experimental Setup

  • Neutrino Beam: Utilizes the NuMI (Neutrinos at the Main Injector) beam, which is one of the most intense neutrino beams in the world.
  • Detectors: Consists of two detectors:
    • Near Detector: Located at Fermilab, it measures the unoscillated neutrino beam composition.
    • Far Detector: Located 810 kilometers away in Ash River, Minnesota, it detects the oscillated beam and identifies electron neutrino appearances

Key Technologies and Methods

  • Liquid Scintillator Detectors: Both detectors use liquid scintillator technology to detect interactions by producing light when neutrinos interact with the detector material.
  • Deep Learning and Data Analysis: NOvA employs advanced machine learning techniques to improve event classification and data analysis, significantly enhancing sensitivity to oscillation parameters​.

Subatomic Particles

  • Subatomic particles are the fundamental constituents of matter, and they fall into two main categories: elementary particles and composite particles.

Elementary Particles

  • These particles are not composed of other particles. They include quarks, leptons, and gauge bosons.

Category

Particle

Symbol

Charge

Mass (MeV/c²)

Spin

Generation

Interactions

Quarks

Up Quark

u

+2/3 e

2.2

1/2

1

Strong, Weak, EM

Down Quark

d

-1/3 e

4.7

1/2

1

Strong, Weak, EM

Charm Quark

c

+2/3 e

1,280

1/2

2

Strong, Weak, EM

Strange Quark

s

-1/3 e

96

1/2

2

Strong, Weak, EM

Top Quark

t

+2/3 e

173,000

1/2

3

Strong, Weak, EM

Bottom Quark

b

-1/3 e

4,180

1/2

3

Strong, Weak, EM

Leptons

Electron

e⁻

-1 e

0.511

1/2

1

Weak, EM

Electron Neutrino

νₑ

0

<0.0000022

1/2

1

Weak

Muon

μ⁻

-1 e

105.66

1/2

2

Weak, EM

Muon Neutrino

νμ

0

<0.17

1/2

2

Weak

Tau

τ⁻

-1 e

1,776.86

1/2

3

Weak, EM

Tau Neutrino

ντ

0

<18.2

1/2

3

Weak

Gauge Bosons

Photon

γ

0

0

1

-

EM

Gluon

g

0

0

1

-

Strong

W Boson

W⁺, W⁻

±1 e

80,379

1

-

Weak

Z Boson

Z⁰

0

91,188

1

-

Weak

Higgs Boson

H⁰

0

125,100

0

-

-

Composite Particles

  • These particles are composed of quarks held together by the strong force. They include baryons and mesons.

Category

Particle

Symbol

Charge

Mass (MeV/c²)

Spin

Quark Composition

Interactions

Baryons

Proton

p

+1 e

938.27

1/2

uud

Strong, Weak, EM

Neutron

n

0

939.57

1/2

udd

Strong, Weak

Mesons

Pion

π⁺, π⁻, π⁰

±1 e, 0

139.57, 135.0

0

u anti-d, d anti-u, (u anti-u or d anti-d)

Strong, Weak

Kaon

K⁺, K⁻, K⁰

±1 e, 0

493.67

0

u anti-s, s anti-u

Strong, Weak

Fundamental Forces and Their Mediators

Force

Mediator

Symbol

Relative Strength

Range

Gravitational

Graviton*

G

Weakest

Infinite

Electromagnetic

Photon

γ

10³⁶ times gravity

Infinite

Weak Nuclear

W and Z Bosons

W⁺, W⁻, Z⁰

10²⁵ times gravity

Very short (~10⁻¹⁸ m)

Strong Nuclear

Gluon

g

10³⁸ times gravity

Very short (~10⁻¹⁵ m)

*Graviton is hypothetical and has not yet been observed.

Explanation of Terms

  • Charge: Represents the electric charge of the particle.
  • Mass (MeV/c²): The mass of the particle in mega-electronvolts per speed of light squared.
  • Spin: Intrinsic form of angular momentum carried by particles.
  • Generation: Refers to the different families of quarks and leptons based on their mass and interaction strength.
  • Interactions: Types of fundamental forces the particle participates in.

Global Efforts in Neutrino Research

Must Read Articles:

Classification of Elementary Particles

W-Boson 

Higgs Boson


Sources:

HINDU

PRACTICE QUESTION

Q: Consider the following statements about subatomic particles:

  1. Quarks are the fundamental constituents of protons and neutrons.
  2. Electrons are leptons and are not made up of smaller particles.
  3. The Higgs boson is responsible for providing mass to other particles.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2, and 3

Answer: (d)