Unambiguous Evidence for Weak Neutral Currents

In summary, the observation of (anti muon neutrino) + (electron) -> (anti muon neutrino) + (electron) constitutes unambiguous evidence for weak neutral currents. However, the observation of (anti electron neutrino) + (electron) -> (anti electron neutrino) + (electron) does not violate charge conservation, so the third diagram in Feynman's diagrams (an electron decaying to a muon neutrino) is impossible.
  • #1
hob
6
0

Homework Statement



What observation of the process: (anti muon neutrino) + (electron) -> (anti muon neutrino) + (electron) constitutes unambiguous evidence for weak neutral currents,

whereas the observation of (anti electron neutrino) + (electron) -> (anti electron neutrino) + (electron)

The Attempt at a Solution




The solution is the first one:

{www}.scribbleproductions.co.uk/stuff/fine1.jpg

Since the second reaction can undergo via W+ as well as Z0:

{www}.scribbleproductions.co.uk/stuff/fine2.jpg


My question is in the Feynman diagrams, why could you not have this for example:

An electron decaying to a muon neutrino ?

{www}.scribbleproductions.co.uk/stuff/fine3.jpg

Apparently the weak interaction also violates charge conservation, but I have never seen a possible reaction with a Feynman diagram that is violated at the vertices's.

Many thanks for any help :)
 
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  • #2
hob said:

Homework Statement



What observation of the process: (anti muon neutrino) + (electron) -> (anti muon neutrino) + (electron) constitutes unambiguous evidence for weak neutral currents,

whereas the observation of (anti electron neutrino) + (electron) -> (anti electron neutrino) + (electron)

The Attempt at a Solution




The solution is the first one:

{www}.scribbleproductions.co.uk/stuff/fine1.jpg

Since the second reaction can undergo via W+ as well as Z0:

{www}.scribbleproductions.co.uk/stuff/fine2.jpg


My question is in the Feynman diagrams, why could you not have this for example:

An electron decaying to a muon neutrino ?

{www}.scribbleproductions.co.uk/stuff/fine3.jpg

Apparently the weak interaction also violates charge conservation, but I have never seen a possible reaction with a Feynman diagram that is violated at the vertices's.

Many thanks for any help :)

The weak interaction does NOT violate charge conservation! So your third diagram is impossible. Charge is always conserved
 
  • #3
nrqed said:
The weak interaction does NOT violate charge conservation! So your third diagram is impossible. Charge is always conserved

Thanks for that, I was a bit uneasy to see charge violation.

Does weak violate anything to do with charge? I remember seeing something about charge violation that only the weak does not strong or e.m

Regards,
 

1. What is the significance of "Unambiguous Evidence for Weak Neutral Currents"?

The discovery of Weak Neutral Currents (WNC) was a major milestone in the field of particle physics. It provided crucial evidence for the unification of the electromagnetic and weak forces, as predicted by the Standard Model of particle physics. This discovery helped to confirm the validity of the Standard Model and opened up new avenues for research in this field.

2. How was "Unambiguous Evidence for Weak Neutral Currents" obtained?

The discovery of Weak Neutral Currents was made possible by the experiments conducted at the Super Proton Synchrotron (SPS) at CERN in the 1970s. These experiments involved colliding protons and antiprotons at high energies and analyzing the resulting collision products. By carefully studying the properties of these particles, scientists were able to detect the presence of WNC and confirm their existence.

3. What are Weak Neutral Currents and how do they differ from Strong and Electromagnetic Currents?

Weak Neutral Currents are one of the four fundamental forces of nature, along with the strong, electromagnetic, and gravitational forces. They are responsible for interactions between subatomic particles, specifically the interaction between charged particles and neutral particles. Unlike the strong and electromagnetic forces, which are mediated by particles with charge, WNC are mediated by particles with no charge, known as Z bosons.

4. What are the implications of "Unambiguous Evidence for Weak Neutral Currents" in the field of particle physics?

The discovery of Weak Neutral Currents had a significant impact on the field of particle physics. It provided strong evidence for the unification of the electromagnetic and weak forces and helped to confirm the validity of the Standard Model. It also opened up new avenues for research, such as the search for the Higgs boson, which was predicted by the Standard Model to give particles their mass through interactions with WNC.

5. How does the discovery of Weak Neutral Currents contribute to our understanding of the universe?

The discovery of Weak Neutral Currents has greatly contributed to our understanding of the universe and its fundamental forces. It has helped to explain the behavior of subatomic particles and how they interact with each other. Furthermore, it has confirmed the predictions of the Standard Model and provided a strong foundation for further research and discoveries in the field of particle physics.

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