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LHC, what then?

  1. Jan 2, 2016 #1
    It seems that LHC have done its job.
    Higgs boson is found, unfortunately of the most boring variety - bad news for SUSY.
    Anyway, it seems that SUSY is getting dead like a dodo.
    No micro-BH either, so no new dimensions to investigate.
    Nothing beyond Standard Model.
    So it seems that any "new physics" might be only at GUT scale 10^16 GeV at the earliest.
    So there is 10^12 GeV gap.
    My suspicion: there may be not much incentives to build new accelerator.
    LHC may well be the last and if one delivering 100TeV by any chance is built and found nothing new, then that will be it.
    Any comments on that?
  2. jcsd
  3. Jan 2, 2016 #2

    Vanadium 50

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    The LHC has taken 0.1% of the data that it will ever take. Drawing conclusions about what it didn't find after 0.1% is like deciding the World Series after the first inning on opening day.
    Last edited by a moderator: Jan 2, 2016
  4. Jan 2, 2016 #3


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    Added to Vanadium 50's:
    Well in my opinion, once an accelerator starts operating there can be ideas and plans for a new one, but the first has to finish its job first. The LHC for example took over FermiLab's accelerator (and some may whine, it did it too soon o0))
    There are plans and talks for new generation accelerators with higher CoM energies (like the ILC etc). But these new colliders will need at least a decade to be constructed, and so CERN's lifetime is not going to be over soon : it has to collect more data and this data should be analyzed for the next years.
    Finding new stuff might be exciting, but understanding better what we might think we know is even more important. LHC is not only dedicated into searching for new physics but there are a lot of efforts in understanding better the already known stuff not to mention how it feeds the rest of non-physical fields (Nobody would fund CERN if the only thing it was supposed to do was to search and find one or more hypothetical particles necessary only for physicists).
    Then for the gap:
    Maybe SUSY is in 100TeV, you can't possibly know - however it's unlikely because it loses then its "privileges" for which we came to like it. But you can't predecide where nature chooses to show itself and break up your plans or ideas. Maybe there is no SUSY and the next particle we find will be at 30TeV and be a Higgs-like particle). Higher energies can also help you put boundaries in the hypothetical particles (as an example for the SSM W', in the 8TeV run the mass for the W' was found by ATLAS to be at >3.2TeV, while for the Run 2 analysis that limit went to >4TeV)
  5. Jan 2, 2016 #4


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    There are many searches that didn't even start because we need more data - and all searches will be able to extend their search range with more data (a factor of ~1000!).
    Even if no new particles show up, the experiments will deliver a wide range of measurements that help to exclude possible new models, and measure various standard model parameters with an unprecedented precision. Top physics, precision electroweak physics, tetraquarks/pentaquarks, new mesons and baryons, flavor physics, rare decays... there is more than just the Higgs. And the Higgs measurements didn't stop with its discovery either, the next years will allow to measure its parameters with increasing precision.

    Even without new particles, there is a good physics motivation for the ILC to measure top and Higgs (and some Z and W properties) more precisely than the LHC can.

    A possible ~100 TeV collider: well... let's see.
  6. Jan 2, 2016 #5


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    Recently the LHC has turned up some data that is not readily explained. A lot more experiments need to be done before its lifetime ends.

    Google "large hadron collider news" for the month of December 2015.
  7. Jan 2, 2016 #6


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    We have a thread about the diphoton excess. The overall significance is not negligible, but it is too early for conclusions.

    The LHCb deviations from lepton universality and the odd effects in one of their angular analyses are interesting as well. Same thing here: strange, but more data is needed.
  8. Jan 8, 2016 #7
  9. Jan 15, 2016 #8
    Getting 1000 times the events means improving the LHC's sensitivity to new particles by a factor of sqrt(1000) or about 30. That may be enough to discover new particles that do not interact by QCD and that do not produce signals as clean as the Higgs particle produces. This would include some of the lighter SUSY particles.
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