What are the different decay processes shown in this Feynman diagram?

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SUMMARY

The forum discussion centers on the decay processes illustrated in a momentum-space Feynman diagram, specifically focusing on the interactions involving electrons, positrons, and photons. The processes discussed include ##e^{-} \rightarrow e^{+} + \gamma##, ##e^{+} \rightarrow e^{-} + \gamma##, and ##\gamma \rightarrow e^{+} + e^{-}##, with the latter being a clear decay of a photon into an electron-positron pair. The conversation also delves into the Higgs boson's decay mechanisms, particularly the process ##h \rightarrow e^{-} + e^{+}##, which is allowed if the Higgs mass exceeds twice the electron mass. The discussion concludes that higher-order decay processes exist but are suppressed due to additional vertices and phase space constraints.

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  • Familiarity with the Standard Model of particle physics, particularly Higgs boson properties.
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  • #31
failexam said:
I am adding that line, because each interaction vertex must have three lines popping out of it, with the Higgs for one line and the fermion and anti-fermion on the other two lines
But without having that extra higgs you still satisfy that! You just have one vertex less.
 
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  • #32
Got it!

Is this the only tree-level Feynman diagram for this process?
 
  • #33
No. You have two diagrams. One where the electron of the initial vertex is external and one where the positron is.
 
  • #34
I see! So, for a process like

$$h \rightarrow e^{+} + e^{-} + \mu^{+} + \mu^{-}$$

you have only the following two tree-level Feynman diagrams, right?

https://i.imgsafe.org/79327227a1.jpg

https://i.imgsafe.org/7932eec9b7.jpg
 
  • #35
No. You also have the diagrams where the initial vertex is with the electron line.
 
  • #36
Got it!

So, you have two tree-level Feynman diagrams for

$$h \rightarrow e^{+} + e^{-} + e^{+} + e^{-} $$

https://i.imgsafe.org/79814d363d.jpg

and four tree-level Feynman diagrams for

$$h \rightarrow e^{+} + e^{-} + \mu^{+} + \mu^{-}$$

https://i.imgsafe.org/7981a81e80.jpg

https://i.imgsafe.org/79820c6447.jpg,

right?
 
  • #37
wouldnt that work? h \rightarrow hh \rightarrow 2l 2l'?
Also these are not tree diagrams...
 
  • #38
ChrisVer said:
wouldnt that work? h \rightarrow hh \rightarrow 2l 2l'?
Also these are not tree diagrams...

Which ones are not tree-level Feynman diagrams?
 
  • #39
failexam said:
Which ones are not tree-level Feynman diagrams?
that was a conceptual mistake...
 
  • #40
Right, so all of the diagrams that I posted are tree-level diagrams, right?
 

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