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Are there any other particle predictions by the standard model?

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  • $\begingroup$ Yes, and no. Some variations on the theory have multiple Higgs particles (or as I like to call them, Higgs & Biggs). $\endgroup$
    – David H
    Nov 27, 2013 at 12:04
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    $\begingroup$ possible duplicate of Higgs boson in LHC $\endgroup$ Nov 27, 2013 at 12:05
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    $\begingroup$ The Standard Model has just one Higgs. $\endgroup$
    – pfnuesel
    Nov 27, 2013 at 12:07
  • $\begingroup$ I had VTCed as "Unclear what you' are asking", actually. I'm a bit annoyed when the system puts VTC reasons in my mouth. $\endgroup$ Nov 27, 2013 at 12:46
  • $\begingroup$ Why duplicate? I searched Google for my question and nothing showed up. Do you expect people with a similar question as mines to search for "Higgs boson in LHC"? $\endgroup$ Nov 28, 2013 at 10:52

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Now that we have seen the Higgs boson, all the particles predicted by the Standard Model have been discovered.

The penultimate particle to be discovered was the tau-neutrino at Fermi-Lab in 2000. The antepenultimate particle to be discovered was the top quark, also at Fermi-Lab in 1995. For a complete timeline, see e.g. this wiki page.

There are, of course, theories that predict even more particles (so-called Beyond the Standard Model physics), but no such particles have been directly observed.

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  • $\begingroup$ +1, though you should add that there have been some signs of supersymmetric particles, and that the 125 GeV Higgs is also an indicator of Supersymmetry/MSSM/M-Theory compactifications. $\endgroup$ Nov 27, 2013 at 12:37
  • $\begingroup$ @DIMension10 why is a 125 GeV Higgs an indication to correctness of those theories? Please provide references. $\endgroup$ Nov 27, 2013 at 12:40
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    $\begingroup$ @TheQuantumPhysicist: See Reference 4, Reference 23, Reference 24, Reference 25, Reference 26, Reference 27, Reference 28, and Referencee 29, here. Specifically, Reference 4. $\endgroup$ Nov 27, 2013 at 12:44
  • $\begingroup$ @DIMension10 what indications of supersymmetric particles? Experimental hints? $g-2$? DM? $\endgroup$
    – innisfree
    Nov 27, 2013 at 14:46
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    $\begingroup$ There are no compelling hints of supersymmetric particles in data so far, and no strong sense in which a 125 GeV Higgs constitutes evidence for supersymmetry. The fact that certain supersymmetric theories with a split spectrum predict a Higgs mass near 125 GeV is interesting, and we should certainly be looking for experimental evidence of such theories, but there is no evidence so far. The Standard Model with a 125 GeV Higgs is a consistent, but highly fine-tuned, theory. $\endgroup$
    – Matt Reece
    Nov 27, 2013 at 16:43

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