Comments about "CP violation" in Wikipedia

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Contents

• 1. Overview
• 2. History
• 2.1 P-symmetry
• 2.2 CP-symmetry
• 3. Experimental status
• 3.1 Indirect CP violation
• 3.2 Direct CP violation
• 4. CP violation in the Standard Model
• 5. Strong CP problem
• 6. Matter–antimatter imbalance
• 7. See also

Reflection

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Introduction

The article starts with the following sentence.

In particle physics, CP violation is a violation of CP-symmetry (or charge conjugation parity symmetry): the combination of C-symmetry (charge conjugation symmetry) and P-symmetry (parity symmetry). CP-symmetry states that the laws of physics should be the same if a particle is interchanged with its antiparticle (C-symmetry) while its spatial coordinates are inverted ("mirror" or P-symmetry).

It would be better to write: Applicable Laws of physics and indicate which these are. For example with the weak force.

The discovery of CP violation in 1964 in the decays of neutral kaons resulted in the Nobel Prize in Physics in 1980 for its discoverers James Cronin and Val Fitch.

That means there exists no CP-symmetry.

1. Overview

2. History

2.1 P-symmetry

The first test based on beta decay of cobalt-60 nuclei was carried out in 1956 by a group led by Chien-Shiung Wu, and demonstrated conclusively that weak interactions violate the P-symmetry or, as the analogy goes, some reactions did not occur as often as their mirror image.

This experiment is very important to demonstrate, understand and explain physical processes.

However, parity symmetry still appears to be valid for all reactions involving electromagnetism and strong interactions.

2.2 CP-symmetry

In 1956 Reinhard Oehme in a letter to Chen-Ning Yang and shortly after, Boris L. Ioffe, Lev Okun and A. P. Rudik showed that the parity violation meant that charge conjugation invariance must also be violated in weak decays.

Charge violation was confirmed in the Wu experiment and in experiments performed by Valentine Telegdi and Jerome Friedman and Garwin and Lederman who observed parity non-conservation in pion and muon decay and found that C is also violated.

All these experiments are very important to demonstrate, understand and explain physical processes.

Charge violation was more explicitly shown in experiments done by John Riley Holt at the University of Liverpool.

3. Experimental status

3.1 Indirect CP violation

3.2 Direct CP violation

4. CP violation in the Standard Model

5. Strong CP problem

6. Matter–antimatter imbalance

7. See also

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