Feynman diagram of secondary Sigma plus decay

In summary, the Feynman diagram for the Sigma plus decay to a positive pion and a neutron involves a W exchange and photon/gluon emission to create a d dbar pair. This is a rearrangement of the primary decay to a neutral pion and a proton, and the BF's are slightly different due to differences in mass and alpha values.
  • #1
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Can someone describe the Feynman diagram for the Sigma plus decay to a positive pion and a neutron? I'm fine with the primary decay to the neutral pion and a proton. There appears to be insufficient down quarks created.
 
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  • #2
uus > ud~ u d d

Well one d d~ set can be made with a photon/gluon, while the s-> d can be a loop-level FCNC.

OR

uus : s---u
uus : u---d
via a W exchange, and the d dbar pair is made with a photon/gluon emission.
 
  • #3
Look at the BF's - they are equal for p pi0 and n pi+, so we're not talking about FCNC loops.

You have uus --> uud + ddbar (p pi0)
and uus --> udd + udbar (n pi+)

This is just a rearrangement, which explains their equality.
 
  • #4
Thanks guys. The BF's are actually not 50/50 but 52/48. Why should they be slightly different? Does the fact that alpha for p pi0 (36 deg) and for n pi+ (167 deg) relevant for this? Appreciate your comments.
 
  • #5
The masses aren't identical for n and p, nor pi+ and pi0.
 

What is a Feynman diagram of secondary Sigma plus decay?

A Feynman diagram is a visual representation used in particle physics to depict the interactions between subatomic particles. In the case of secondary Sigma plus decay, the diagram illustrates the decay of a Sigma plus particle into a Lambda baryon and a positive pion.

How is the decay of Sigma plus particles studied using Feynman diagrams?

Feynman diagrams are used to study the decay of Sigma plus particles by showing the possible paths of particle interactions. By analyzing these diagrams, scientists can determine the probabilities of different decay processes and compare them to experimental results.

What information can be gained from a Feynman diagram of secondary Sigma plus decay?

A Feynman diagram can provide information about the particles involved in the decay process, their energy and momentum, and the interactions between them. It can also help determine the relative likelihood of different decay pathways.

How does the Feynman diagram of secondary Sigma plus decay relate to conservation laws?

The Feynman diagram of secondary Sigma plus decay follows the laws of conservation of energy and momentum. This means that the total energy and momentum of the initial particles must be equal to the total energy and momentum of the final particles.

What other applications does the Feynman diagram of secondary Sigma plus decay have?

Feynman diagrams are used in many areas of particle physics, including the study of other decays, particle interactions, and the behavior of subatomic particles in high-energy collisions. They are also used in theoretical calculations and predictions of particle behavior.

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