.Higgs Boson Decay: Does the Third Diagram Exist?

In summary, The conversation discusses a doubt about a specific Higgs boson decay, specifically H -> c+\bar{s}+W^-, where c is the charm quark and \bar{s} the anti strange quark. The third diagram in the process is confirmed to exist, although the s quark cannot be on-shell. It is noted that the Higgs coupling scales with the mass of the particle-antiparticle pair being coupled to, with the coupling to ##s\bar{s}## being smaller than ##c\bar{c}## and ##W^+W^-##. The tree-level diagrams involving ##Hs\bar{s}## and ##Hc\bar{c}## are expected to
  • #1
PLuz
64
0
Hello,

I had a doubt about a specific Higgs boson decay.

In the process [itex]H[/itex] -> [itex]c[/itex]+[itex]\bar{s}[/itex]+[itex]W^-[/itex], where [itex]c[/itex] is the charm quark, [itex]\bar{s}[/itex] the anti strange quark, in tree level I wrote the diagrams sent in attachment.

View attachment Diagram 1.pdf

View attachment Diagram 2.pdf

View attachment Diagram 3.pdf

My question is: does the third diagram exist? I do know that the [itex]s[/itex] quark can't decay to the charm quark since it's mass is inferior to the mass of the charm quark. But in that diagram the strange quark is virtual so...there comes my confusion...

Thank you
 
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  • #2
Yes, it exists. The s can't be on-shell in that process; but, then, the c can't be on-shell in diagram 2 either, so there's not really that big a distinction.
 
  • #3
oh you're right. I was so focused in the quarks' masses that I didn't even think about the W boson. Thank you very much
 
  • #4
You should also note that the Higgs coupling scales with with the mass of the particle-antiparticle pair being coupled to. So the coupling to ##s\bar{s}## is far smaller than that to ##c\bar{c}##, which is itself almost two orders of magnitude smaller than the coupling to ##W^+W^-##.

It is actually expected that the tree-level diagrams involving ##Hs\bar{s}## and ##Hc\bar{c}## give a smaller contribution than the one-loop diagram involving ##Ht\bar{t}## for many decay channels (though perhaps not the one you are considering).
 
  • #5
Indeed I was only considering tree level and this decays but that's really interesting.

I am to draw the contributions of each diagram and compare to the total width of the higgs in the not excluded regions by the LHC and LEP and that is a nice conclusion that I can take.

Thank you
 
  • #6
I never saw this decay in any diagram of the branching fractions, but as I would expect H->WW->Wcs as dominating channel, it might be included in the WW part.

"not excluded regions" is basically some region close to 125 MeV now, and probably just 125 MeV +- resolution after the presentations next week.
 

FAQ: .Higgs Boson Decay: Does the Third Diagram Exist?

What is the Higgs Boson Decay?

The Higgs Boson Decay is a process in which the Higgs Boson particle, also known as the "God particle," decays into other particles. This process is a crucial step in understanding the fundamental forces and particles that make up our universe.

Why is the Higgs Boson Decay important?

The Higgs Boson Decay is important because it provides evidence for the existence of the Higgs Boson particle and helps to explain how particles acquire mass. It also helps to validate the Standard Model of particle physics and can potentially lead to new discoveries in the field.

What are the three decay diagrams of the Higgs Boson?

The three decay diagrams of the Higgs Boson are the "gluon fusion" diagram, the "vector boson fusion" diagram, and the "associated production" diagram. These diagrams represent different ways in which the Higgs Boson can decay into other particles.

Does the third diagram of Higgs Boson decay exist?

According to current research and experiments, the third diagram of Higgs Boson decay, the "associated production" diagram, has been observed and exists. However, scientists are still studying and exploring this process to gain a deeper understanding of the Higgs Boson particle.

How does the decay of the Higgs Boson affect the stability of our universe?

The decay of the Higgs Boson does not directly affect the stability of our universe. However, it plays a crucial role in understanding the fundamental forces and particles that govern the universe's stability and evolution. The discovery and study of the Higgs Boson provide valuable insights into the origins and future of our universe.

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