Why CP symmetry is violated in weak interaction?

In summary: The mathematical construction itself would work with a chiral symmetric theory as well.In summary, CP violations are a property of the Universe and we don't know why they happen.
  • #1
ndung200790
519
0
Please teach me this:
Why is CP symmetry violated in electro-weak interaction? Is it correct that because of the mass of neutrino is zero(so that the left and righ neutrinos do not mix with each other)?
Thank you very much in advance.
 
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  • #2
ndung200790 said:
Please teach me this:
Why is CP symmetry violated in electro-weak interaction? Is it correct that because of the mass of neutrino is zero(so that the left and righ neutrinos do not mix with each other)?
Thank you very much in advance.
Mass of neutrino is not zero - you seem to be using an old source.

IFAIK: the correct answer to your question is "we don't know".
It seems to be a property of the Universe.

We also have to be careful with "why" questions. Try rewording as a "how" or "what" or something - we leave "why" to philosophers. Thus I have interpreted your question as "what is it about the electroweak interaction that leads to CP violations?"
 
  • #3
So,from weak interaction theory(meaning massive boson gauge theory) we can not derive the left-righ asymmetry?
 
  • #4
It is an empirical result, that is my understanding - yes.

We can describe it in the math, and several models for underlying behavior have been proposed which give CP violations ... however, the models don't give anything like the correct magnitudes.

You'll see from the gauge theory that the CP violation it is pretty much plugged in. There are some clues in the way the strong interaction is CP-symmetric. You'll meet the different ideas as you progress. I'm worried that if I try to describe them here, I'll just confuse you more or inadvertently mislead you.

It is possible that things have advanced a bit since I last looked, but a quick trawl suggests "not substantially". I'll leave it to the others to contradict me :)

Welcome to the edge of known physics.
Exciting isn't it?

You should probably find a theoretical physicist in your college working on this.
 
  • #5
ndung200790 said:
So,from weak interaction theory(meaning massive boson gauge theory) we can not derive the left-righ asymmetry?

No, we can't.

Constructing the SM model Lagrangian with it's U(1)*SU(2) structure in the el.-weak sector and adding the Higgs boson nobody else but nature tells you that you have to have to break chiral symmetry explicitly in the Lagrangian. The mathematical construction itself would work with a chiral symmetric theory as well.
 

Related to Why CP symmetry is violated in weak interaction?

1. Why is CP symmetry important in physics?

CP symmetry, also known as Charge-Parity symmetry, is an important concept in physics because it relates to the fundamental laws of nature. It states that the laws of physics should be the same when particles are replaced by their anti-particles (C symmetry) and when the spatial coordinates are inverted (P symmetry). Violations of CP symmetry can provide valuable insights into the underlying symmetries and laws of our universe.

2. What is the role of weak interaction in CP symmetry violation?

Weak interaction is one of the four fundamental forces in nature and it plays a crucial role in CP symmetry violation. The weak force is responsible for the decay of particles and it is the only force that can change the flavor of elementary particles. This flavor change is an essential component in the violation of CP symmetry.

3. How was CP symmetry violation first discovered?

CP symmetry violation was first observed in 1964 by physicists James Cronin and Val Fitch in their experiments on the decay of neutral kaons. They found that the decays of these particles did not follow the expected CP symmetry, leading to the discovery of CP violation in weak interactions.

4. What are some explanations for CP symmetry violation?

There are currently several proposed explanations for CP symmetry violation, including the Standard Model of particle physics and theories of supersymmetry. One theory suggests that CP symmetry is violated due to the interference between two different types of weak interactions, while another theory proposes that it is a result of the complex phase in the quark mixing matrix.

5. What are the potential implications of CP symmetry violation?

The discovery of CP symmetry violation has had a significant impact on our understanding of the universe. It has helped to explain why matter is more abundant than anti-matter in the universe and has provided insights into the early stages of the universe's formation. Additionally, CP violation is being studied in experiments to search for new physics beyond the Standard Model.

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