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Scientific implications of latest LHC SUSY beauty quark

  1. Aug 1, 2015 #1

    LHC Keeps Bruising 'Difficult to Kill' Supersymmetry

    Previous attempts at measuring the beauty quark's rare transformation into a so-called "up quark" had yielded conflicting results. That prompted scientists to propose an explanation beyond the Standard Model -- possibly supersymmetry.

    NEWS: 'Perfect' Electron Roundness Bruises Supersymmetry

    But the latest observations were "entirely consistent with the Standard Model and removes the need for this hypothesis" of an alternative theory, Guy Wilkinson, leader of LHC's "beauty experiment" told AFP

    Implications for MSSM and BSM with this latest result in combination to earlier null results for SUSY?

  2. jcsd
  3. Aug 1, 2015 #2
    Great stuff. Thanks for posting. Some of the early quark stuff is what drew me to physics in my youth.
  4. Aug 1, 2015 #3
    no problem. IMO LHC will not find evidence of Supersymmetry in lhc run 2 b/c nature does not take advantage of this symmetry.
  5. Aug 1, 2015 #4


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    In case anyone is curious here is the technical article published 27 July in Nature Physics. For now at least it seems "open access" you don't need a subscription to read. But it is very technical.

    Kodama your link is to Discovery, essentially the same article seems available at Phys.org---conceivably it might be useful to have the alternative link:
    New blow for 'supersymmetry' physics theory
    July 27, 2015 by Mariette Le Roux
  6. Aug 2, 2015 #5
    marcus do you think these blows to susy increase interest in loop and allied field?
  7. Aug 4, 2015 #6


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    The electron dipole moment measurement reported seems to be the same one that I blogged about back in October 2013 when the preprint came out, http://dispatchesfromturtleisland.blogspot.com/2013/10/signal-at-140-gev-was-flawed-analysis.html which was published in 2014. (The press release referenced is from December 2013). Thus, while it is important, it isn't exactly "breaking news".

    Jester commenting on the finding at the time said that to oversimplify superpartners were unlikely to exist below about 10 TeV given that value.
  8. Aug 5, 2015 #7
    so it would appear that LHC would not find any evidence of SUSY in LHC run 2 @ 13TEV. does naturalness SUSY exist?
  9. Aug 5, 2015 #8


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    All CERN publications are open access, but that is not necessary - all experimental high-energy physics publications have a preprint version on arXiv which gives full access as well.

    The new measurement is a bit more precise than previous ones, but it does not solve the inclusive vs. exclusive puzzle for the measured quantity - there are two sets of measurements with different approaches, and they lead to two groups of measured values that are not in agreement with each other.
    Run 2 just started, taking sufficient data will take a while. First results from searches (especially black holes and other exotic very heavy stuff) might appear as early as end of August or early September, but many studies will need at least the full 2015 dataset to improve the limits relative to run 1.
  10. Aug 5, 2015 #9


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    And here is the link to the arXiv version:
    Determination of the quark coupling strength |Vub| using baryonic decays
    LHCb collaboration
    In the Standard Model of particle physics, the strength of the couplings of the b quark to the u and cquarks, |Vub| and |Vcb|, are governed by the coupling of the quarks to the Higgs boson. Using data from the LHCb experiment at the Large Hadron Collider, the probability for the Λ0b baryon to decay into the pμ−ν⎯⎯μ final state relative to the Λ+cμ−ν⎯⎯μ final state is measured. Combined with theoretical calculations of the strong interaction and a previously measured value of |Vcb|, the first |Vub| measurement to use a baryonic decay is performed. This measurement is consistent with previous determinations of |Vub| using Bmeson decays to specific final states and confirms the existing incompatibility with those using an inclusive sample of final states.
    18 pages, 5 figures
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