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A Implications of a new 17 Mev vector boson on Higgs, SUSY

  1. Jun 12, 2016 #1
    regarding this paper

    Evidence for a Protophobic Fifth Force from 8Be Nuclear Transitions
    Jonathan L. Feng, Bartosz Fornal, Iftah Galon, Susan Gardner, Jordan Smolinsky, Tim M. P. Tait, Philip Tanedo
    (Submitted on 25 Apr 2016)
    Recently a 6.8σ anomaly has been reported in the opening angle and invariant mass distributions of e+e− pairs produced in 8Be nuclear transitions. The data are explained by a 17 MeV vector gauge boson X that is produced in the decay of an excited state to the ground state, 8Be∗→8BeX, and then decays through X→e+e−. The X boson mediates a fifth force with a characteristic range of 12 fm and has milli-charged couplings to up and down quarks and electrons, and a proton coupling that is suppressed relative to neutrons. The protophobic X boson may also alleviate the current 3.6σ discrepancy between the predicted and measured values of the muon's anomalous magnetic moment.
    Comments: 6 pages, 2 figures
    Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

    for sake of discussion let us say that these results are valid, and there is indeed a new previously unknown 17mev vector X boson.

    how does this affect the current SM, including virtual loop diagrams?

    i.e Feng et al suggests it can explain the muon 3-sigma anomaly via virtual loop processes

    how does this effect higgs stability and higgs hierarchy?

    what are implications for dark matter?

    implications for SUSY- extension. i.e does it alleviate or make worse things like FCNC. could this 17mev vector X boson be a SUSY partner of a known SM or SUSY particle?

    a SUSY partner of a 17 MeV vector gauge boson X would be a fermion. what would be its properties, mass, stability, dark matter candidacy and would the LHC be able to see its SUSY-partner?

    lastly, if this x-boson and the earlier LHC 750 GeV diphoton excess boson are both validated, how does the 2 taken together effect the preceding physics? i.e a standard model plus both a 17mev vector boson and 750 gev "scalar" boson on higgs hiearchy, SUSY, dark matter. could these 2 new particles be a part of a hidden sector? i.e the SUSY-partner of a 750 GEV scalar boson is also a fermion.
     
  2. jcsd
  3. Jun 12, 2016 #2

    mfb

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    Very unlikely - the same researchers previously found various other bosons that all disappeared in later experiments, with no explanation where they went. In other words, they simply don't understand their experiments.

    I'm also not convinced that they checked compatibility with absolutely everything. Various fixed-target exoeriments should produce such a boson which should appear via the decay products.
    At least that hypothetical boson itself cannot be dark matter, as it is short-living.
     
  4. Jun 12, 2016 #3
    this boson though could couple to dark matter?
     
  5. Jun 13, 2016 #4

    mfb

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    Well everything can couple to dark matter, and even if the boson exists it doesn't look very useful experimentally. You can see the ##e^- e^+## decay, invisible decay modes would be hard to study.
     
  6. Jun 13, 2016 #5

    Garlic

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    What does protophobic mean? It sounds like they made it up.
     
  7. Jun 13, 2016 #6

    mfb

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    It doesn't couple to protons, or at least its coupling to protons is very small. It is the same concept as "leptophobic" (doesn't couple to leptons), "fermiophobic" (doesn't couple to fermions), "hadrophobic" (doesn't couple to hadrons) and so on.
     
  8. Jun 13, 2016 #7
    they suggest it can explain the muon magnetic unanimous moment discrepancy.

    as a vector boson wouldn't it mediate a new force?

    in SUSY would its SUSY partner a fermion be stable and if so a possible dark matter component.
     
  9. Jun 13, 2016 #8

    mfb

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    Calling something a force gets a bit arbitrary in QCD. It would be a new interaction, sure.
    I don't think that can be determined just based on existing measurements.
     
  10. Jun 13, 2016 #9
    btw this article
    http://blogs.scientificamerican.com/guest-blog/is-particle-physics-about-to-crack-wide-open/

    Is Particle Physics About to Crack Wide Open?
    Hints of an unexpected new particle could be confirmed within days—and if it is, the Standard Model could be going down

    the rumors are that more data LHC is producing may confirm the 750 GEV boson within weeks.

    basically same set of issues. how does this fit in SM and SUSY and higgs hierarchy?

    with a mass of 750 GEV it seems to suggest there is new physics close to the EW scale.
     
  11. Jun 13, 2016 #10

    mfb

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    It is a fact that the 2016 dataset exceeds the 2015 one already (since yesterday). "May confirm" is an empty statement - getting larger datasets can always either confirm or not confirm things seen in smaller datasets. It is not certain, but expected, that first results are shown beginning of August.
    No it does not mean that. It would mean we need an extension of the standard model. In the same way buildings are still built using Newtonian physics instead of general relativity, the SM remains a really good approximation in many measurements, no matter what comes up beyond it.
    Depends on which of the 400 publications you prefer.
     
  12. Jun 13, 2016 #11
    august -ill mark in my calendar

    what is your preferred explanation for 750 gev diphoton if it turns out to be a verified particle. what is the most parsimonious extension of the SM that can accommodate it?

    btw any idea how long it might take to verify a 17mev vector boson? should tevatron or lhc be able to verify or are hadron collisions too messy. would a linear e-p collider able to verify it?
     
  13. Jun 13, 2016 #12

    mfb

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    3rd to 10th to be precise.

    Something that has more particles the LHC can find and study. A bound state of a new interaction? The start of a Kaluza-Klein tower? Some relation to dark matter would be great as well.
    A ~500 MeV positron fixed target experiment should be ideal. But I think the authors should understand their experiments first.
     
  14. Jun 13, 2016 #13
    are there any ~500 MeV positron fixed target experiment in the works ?
     
  15. Jun 13, 2016 #14

    mfb

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    People moved on to higher energies decades ago. Most electron positron colliders should be able to produce those beams with not too much effort, they have positron beams anyway. But currently I don't see the motivation.
     
  16. Jun 13, 2016 #15

    fresh_42

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    This is what me as a layman makes me doubt the results. The energy level is so low that I cannot withstand to think that anything on this level should have been found decades ago.
     
  17. Jun 13, 2016 #16
    discovering a new vector boson isn't motivation? what was LHC for then?

    what about winning a nobel prize ?
     
  18. Jun 14, 2016 #17

    mfb

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    If there would be any reason to expect a boson it would be a motivation. But where is this reason?

    For the LHC, it was clear that it would find something, because without Higgs and without anything else the theory would have broken down at energies the LHC can reach. And indeed, the LHC did find something - the Higgs so far.
     
  19. Jun 14, 2016 #18
    what would be ways to validate or rule out a protophobic 17 mev vector boson, apart from the hungarian researchers, that could be done in doable experiments ?
     
  20. Jun 14, 2016 #19

    mfb

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    Well, the fixed-target experiment...
    Would be quite cheap to set up, various facilities produce GeV electron beams, they can be used for conversion to photons and then electron/positron pairs, select the positron energy with a magnet, let it hit a thin target, then look for electron/positron pairs and measure their invariant mass and angular distribution.
     
  21. Jun 14, 2016 #20
    isn't this worth doing? any research groups attempting to verify this?

    this is a nobel prize level discovery.
     
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