Comments about "Wu experiment" in Wikipedia

This document contains comments about the article Wu experiment in Wikipedia
In the last paragraph I explain my own opinion.

Contents

Reflection

Introduction

The article starts with the following sentence.

1. History

In 1927, Eugene Wigner formalized the principle of the conservation of parity (P-conservation),the idea that the current world and one built like its mirror image would behave in the same way, with the only difference that left and right would be reversed (for example, a clock which spins clockwise would spin counterclockwise if a mirrored version of it were built).
What is the physical implication of this thoughtexperiment.
This principle was widely accepted by physicists, and P-conservation was experimentally verified in the electromagnetic and strong interactions. However, during the mid-1950s, certain decays involving kaons could not be explained by existing theories in which P-conservation was assumed to be true. There seemed to be two types of kaons, one which decayed into two pions, and the other which decayed into three pions. This was known as the τ–θ puzzle.

2. Theory

3. Experiment

3.1 Materials and methods

3.2 Results

In the experiment carried out by Wu, the gamma ray anisotropy was approximately 0.6. That is, approximately 60% of the electrons were emitted in one direction, where as 40% were emitted in the other.
This shows assymmetry.
If parity were conserved in beta decay, the emitted electrons would have had no preferred direction of decay relative to the nuclear spin, and the asymmetry in emission direction would have been close to the value for the gamma rays.
This is an extremely clear demonstration, how important the details of any process are.
However, Wu observed that the electrons were emitted in a direction preferentially opposite to that of the gamma rays with an asymmetry significantly greater than the gamma ray anisotropy value. That is, most of the electrons favored a very specific direction of decay, specifically opposite to that of the nuclear spin
The results greatly surprised the physics community.
The important issue that it is very important to consider the 3D stucture of how the particles interfer with each other.

4. Mechanism and consequences

The results of the Wu experiment provide a way to operationally define the notion of left and right.
Is it not possible to explain the problem in a simpler way?
My impression is that left and right is a concept to be agreed upon by a group of people. It resembles the Nord and South pole definition of magnetized iron; what is Nord and what is South.
When
The Wu experiment has finally solved the Ozma problem which is to give an unambiguous definition of left and right scientifically.
I doubt if this is important. Much more important is the 3D structure of the complex reaction. See below.
At the fundamental level (as depicted in the Feynman diagram on the right), Beta decay is caused by the conversion of the negatively charged (-1/3 e) down quark to positively charged (+2/3 e) up quark by emission of a W− boson; the W− boson subsequently decays into an electron and an electron antineutrino: d --> u + e− + νe.
Beta decay of a neutron consists of two reactions: (1) d--> u + W- and (2) W- --> e− + νe.
The Feynman diagram shows this in 2D with a time axis at the left. IMO this picture is too simple. It is a complex asymmetric process evolving in 3D.
The process starts with a neutron which consists of 3 quarks: 1 up and 2 down. Those

5. Impact and influence

6. See also

Following is a list with "Comments in Wikipedia" about related subjects

Reflection 1 - P-conservation versus P - Violation

P - Conservation means using electromagnetic phenomena that a radio observed in a window should work, which is always the case. Building one is possible because all the components are human made. I have no direct reason to think that this is not true.
A human observing through a mirror is alive, but building one is impossible because we can not build a human being.
A human is a very complex system, consisting of complex molecules. These molecules are build inside the human body, by copying DNA, using a complex mechanism.

Does this not mean that asymmetry in physics is the norm? To be continued.

Reflection 2

Reflection 3

Reference 9
https://link.springer.com/chapter/10.1007/978-4-431-77056-5_4
The Discovery of the Parity Violation in Weak Interactions and Its Recent Developments by Chien-Shiung Wu

It is a great honor and privilege for me to deliver the Nishina Commemorative Lecture.
Dr. Yoshio Nishina made not only fundamental and important contributions to various scientific fields; his great leadership, inspiration and dedication to scientific research and higher education in this country is a most moving and inspiring story to commemorate.
The topic of my talk today on the Discovery of the Parity Violation in Weak Interactions and Its Recent Developments is already twenty-six years old. On January 16, 1957,the world of Physics was suddenly shocked by the news that parity is not conserved. The Jackson Professor Otto Frisch of Cambridge University described the announcement as “the obscure phrase ‘parity is not conserved’ circled the globe like a new gospel.” Why has the news caused such excitement? What is the real meaning of the law of Conservation of Parity? What are the implications and consequences of the overthrow of the law of parity on Physics? Put in the simplest language, it means that the results of this discovery unequivocally proved that many natural phenomena, and also the objects of the microscopic world, are not necessarily symmetrical with respect to left and right. Now, one must be even more puzzled and want to understand why people should be so shocked by the discovery in which things turned out not necessarily left-right symmetrical

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Created: 3 September 2024

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