Yukawa’s theory explained

nuclear physics lecture ( YUKAWAS’S THEORY )

In nuclear physics, Yukawa’s theory plays a crucial role in understanding the strong nuclear force, which binds protons and neutrons together in atomic nuclei. Here’s a more detailed explanation:

1. Nature of the Strong Nuclear Force: The strong nuclear force is one of the four fundamental forces of nature, along with gravity, electromagnetism, and the weak nuclear force. It is responsible for binding protons and neutrons together in the atomic nucleus. Unlike the electromagnetic force, which decreases with distance according to an inverse square law, the strong force acts over very short distances and is highly attractive.
2. Problem of Short-Range Force: Prior to Yukawa’s work, physicists struggled to explain how the strong force could act over such short distances within the nucleus. The electromagnetic force, for example, is mediated by photons, which are massless particles and can thus travel over long distances. However, the strong force needed a different explanation.
3. Yukawa’s Proposal: In 1935, Hideki Yukawa proposed a new theory to explain the strong force. He suggested that the force was mediated by a new particle, which he called the meson. This particle was hypothesized to be intermediate in mass between electrons and protons and to have a short range of action.
4. Mathematical Formulation: Yukawa’s theory was based on a quantum field theory framework. He introduced a new field, now known as the meson field, to describe the exchange of mesons between nucleons (protons and neutrons). This exchange of mesons results in the attractive force between nucleons, which holds the nucleus together.
5. Experimental Confirmation: Yukawa’s theory predicted the existence of the meson as a carrier particle for the strong force. In 1947, the pion (pi-meson) was discovered in cosmic rays by Cecil Powell and his team. This discovery provided experimental confirmation of Yukawa’s theory and demonstrated the existence of the meson as predicted.
6. Implications and Legacy: Yukawa’s theory revolutionized our understanding of the strong force and paved the way for further developments in nuclear physics. The concept of exchange particles mediating fundamental forces became a cornerstone of modern particle physics. Yukawa’s work laid the foundation for the development of quantum chromodynamics (QCD), the theory that describes the strong nuclear force in terms of quarks and gluons.

In summary, Yukawa’s theory provided a theoretical framework for understanding the strong nuclear force and introduced the concept of exchange particles mediating fundamental interactions in nuclear physics