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B How were the properties of the Higgs boson accuratly predicted?

  1. Apr 12, 2016 #1
    What I mean by this is how were the laws of quantum mechanics used to predict that the higgs boson would decay into 2 photons or 4 electrons. I understand that the higgs boson transmits the higgs field, but why would a particle that transmits the higgs field have to decay in that wayand not some other way, why not decay into other particles. Same question with all of the other properties of it that were accuratly predicted.
     
    Last edited: Apr 12, 2016
  2. jcsd
  3. Apr 12, 2016 #2
    Oh boy...you should have just asked for a good textbook on particle physics or quantum field theory.
     
  4. Apr 13, 2016 #3
     
  5. Apr 13, 2016 #4

    ChrisVer

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    Gold Member

    In a few lines...
    I don;t like the view that 'higgs boson transmits the higgs field'... I find it unnecessarily confusing.
    Now to your main point; the Higgs Boson does not decay only in photons or 4 leptons....
    the Higgs boson by theory couples to all the fermions through Yukawa terms in the Lagrangian and to gauge bosons (like WW or ZZ). So it couples to quarks, leptons and gauge bosons... the quarks and gluons are important because that's how the Higgs boson is produced in the first place [when the protons collide]... It then can decay to several channels... it was the photon channel and the ZZ (that results to 4 leptons] that was first observed because if I recall well they give the clearest signal....
    To what the Higgs Boson prefers to couple to depends on its mass, see eg Fig 11.4 here:
    https://pdg.web.cern.ch/pdg/2015/reviews/rpp2015-rev-higgs-boson.pdf
    with [itex]b\bar{b}[/itex] being the dominant decay products of the Higgs...However most of the decays to "QCD" objects (like quarks or gluons or taus), that are seen by the detector as "jets", have a very strong QCD background. I believe eversince the Higgs was discovered more channels were used/observed... one I am sure about is the [itex]\tau^+\tau^-[/itex].

    Now if your question is why it couples to all these; well you need to take some Particle Physics course... the main idea is that everything couples to everything as long as a symmetry permits it, and if it doesn't then you have to find a good reason why not.
     
  6. Apr 14, 2016 #5

    mfb

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    2016 Award

    Staff: Mentor

    There are many decay channels. All channels that do not violate conservation laws happen with some probability. Two photons or four leptons are actually quite rare, but they are experimentally easier to find than other channels.
    The precise numbers are the result of calculations in quantum field theory.
     
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