# Weak Nuclear Force, and Electroweak Theory with FAQs

The weak nuclear force, also known as the weak interaction, is one of the fundamental forces in nature. It is responsible for certain types of radioactive decay and particle interactions involving elementary particles.

The weak force is one of the four fundamental forces, alongside gravity, electromagnetic force, and the strong nuclear force. The weak nuclear force is responsible for certain types of radioactive decay and particle interactions. It is involved in beta( β) decay processes, where a neutron decays into a proton, an electron, and an electron antineutrino.

# What is weak nuclear force?

The weak nuclear force, also known as the weak interaction, is one of the fundamental forces in nature. It is responsible for certain types of radioactive decay and particle interactions involving elementary particles.

The weak force is one of the four fundamental forces, alongside gravity, electromagnetism, and the strong nuclear force. The weak nuclear force is responsible for certain types of radioactive decay and particle interactions. It is involved in beta( β) decay processes, where a neutron decays into a proton, an electron, and an electron antineutrino.

## The correct decay process of a neutron:

The correct decay process of the free neutron at rest: n →p+e-

Where n is a neutron, p is a proton and e-is an electron.

Einstein’s mass-energy relation is given by e=mc2, where m is the Mass defect or Mass of neutron(Mass of proton+ Mass of an electron) and c is the speed of light. Here m and c are constant. However, the above two body decay is unable to explain the continuous energy distribution in β decay of a neutron or a nucleus.

The β decay process was discovered around 1900 and was primarily the decay of a neutron. In the laboratory, a proton, p, and an electron e- are observed as a decay product of a neutron. Therefore the decay of a neutron was considered as two body decay process. For which it was predicted that the kinetic energy of the electron should be a constant. However experimentally, it was observed that the electron kinetic energy has a continuous spectrum. Around 1930, Pauli considering the three-body decay process explained the observed electron energy spectrum as  n →p+e-+ ν̄ e

It is assumed that anti-neutrino(ν̄ e) is massless and possesses negligible energy, and the neutron is at rest, momentum and energy conservation principles are applied.

## Electroweak theory:

The weak force is described by the electroweak theory, which unifies it with the electromagnetic force The electroweak theory is a unified theory in particle physics that combines two fundamental forces of nature such as the electromagnetic force and the weak nuclear force. It describes the behaviour and interactions of elementary particles and their associated fields.

The electroweak theory, proposed in the 1960s by Sheldon Glashow, Abdus Salam, and Steven Weinberg, unifies the electromagnetic and weak forces into a single theory by introducing a new set of particles and symmetries. It introduces a unified electroweak force mediated by four particles: the photon (γ) for electromagnetic interactions and the W+, W-, and Z bosons for weak interactions.

The theory is based on the principle of gauge symmetry, which requires the existence of a gauge field for each force-carrying particle. In the electroweak theory, the electromagnetic and weak forces are described by a unified gauge field known as the electroweak field.

## Important points in understanding the weak nuclear force:

Radioactive Decay: The weak force plays a crucial role in certain forms of radioactive decay. For example, beta decay occurs when a neutron inside an atomic nucleus decays into a proton, emitting an electron (beta particle) and an electron antineutrino. The weak force is responsible for this decay process by facilitating the conversion of a down-type quark in the neutron to an up-type quark, transforming the neutron into a proton.

Lepton Interactions: The weak force governs interactions involving elementary particles called leptons. Leptons include particles such as electrons, muons, and neutrinos. The weak force enables interactions between leptons, causing processes like lepton decay and neutrino interactions.

Neutrinos: Neutrinos are neutral, weakly interacting particles that are produced in various nuclear reactions, such as in the Sun or during radioactive decay. Neutrinos are affected only by weak force and gravity. The weak force allows neutrinos to interact with other particles and participate in processes like neutrino scattering and weak nuclear reactions.

W and Z Bosons: The weak force is mediated by elementary particles called gauge bosons. The W and Z bosons are the force-carrying particles associated with the weak nuclear force. These bosons are electrically charged (W ±) and neutral (Z 0). The exchange of these particles mediates the weak interactions between particles.

Electroweak Unification: The weak nuclear force was unified with the electromagnetic force in the electroweak theory proposed by Sheldon Glashow, Abdus Salam, and Steven Weinberg. This theory describes the electromagnetic and weak forces as different manifestations of a single electroweak force at high energies.

It is important to note that the weak force is short-range and much weaker compared to the electromagnetic and strong nuclear forces. However, it plays a critical role in various fundamental processes, such as the stability and transformations of atomic nuclei and the interactions of elementary particles.

## FAQs of weak nuclear force:

Q: What is the weak nuclear force?

A: The weak nuclear force, also known as the weak interaction, is one of the four fundamental forces in nature. It is responsible for certain types of radioactive decay and particle interactions involving elementary particles.

Q: How does the weak nuclear force work?

A: The weak force is mediated by elementary particles called gauge bosons, specifically the W and Z bosons. It acts on particles that carry weak isospin or weak hypercharge, such as quarks and leptons. The weak force allows for processes like beta decay and neutrino interactions.

Q: What are some examples of a weak nuclear force in action?

A: The weak nuclear force plays a crucial role in processes such as beta decay, where a neutron decays into a proton, emitting an electron (beta particle) and an electron antineutrino. It also governs interactions involving leptons, such as muon decay or neutrino scattering.

Q: How does the weak nuclear force differ from the strong nuclear force?

A: The weak nuclear force and the strong nuclear force are distinct fundamental forces. The weak force governs certain types of particle interactions, while the strong force binds protons and neutrons within the atomic nucleus. The weak force has a much shorter range and is weaker compared to the strong force.

Q: What is the role of the weak nuclear force in particle physics?

A: The weak force is an essential component of the Standard Model of particle physics. It helps explain the behaviour of elementary particles and their interactions. The weak force, together with the electromagnetic force, was unified into the electroweak theory, which describes both forces at high energies.

Q: How does the weak nuclear force relate to neutrinos?

A: Neutrinos are neutral, weakly interacting particles that are affected only by weak force and gravity. The weak force allows neutrinos to participate in weak interactions, such as neutrino scattering and neutrino oscillation.

Q: What are the applications of the weak nuclear force?

A: The weak nuclear force has implications for nuclear physics research, particle physics experiments, and our understanding of the fundamental particles and interactions in the universe. It contributes to our knowledge of radioactive decay processes and plays a role in phenomena such as neutrino detection and astrophysics involving weak interaction

## Conclusion:

The weak nuclear force, also known as the weak interaction, is one of the four fundamental forces in nature. It is responsible for certain types of radioactive decay and particle interactions involving elementary particles. The weak force is involved in processes such as beta decay, where a neutron decays into a proton, emitting an electron (beta particle) and an electron antineutrino. Compared to the electromagnetic and strong nuclear forces, the weak force is relatively short-range and weaker in strength. It is an essential component of the Standard Model of particle physics and contributes to our understanding of the behaviour of elementary particles and their interactions.