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Supersymmetry and Fusion Catalysis

  1. Sep 3, 2012 #1
    I've often been fascinated by the tantalising nature of muon-catalysed fusion, and have recently been pondering it in the context of supersymmetry.

    As a Chemist first and foremost, the nearly-chemical nature of the muon-catalysed fusion process really draws my attention. To my understanding the process goes a little like this:

    You start your hydrogen molecule, perhaps singly ionised :

    H - e - H

    This has a proton/deuteron/triton to proton/deuteron/triton separation of approximately 1.1 angstroms (1x10^-10 m).

    A muon (μ) is introduced. As a negatively-charged lepton, it acts like an electron forming a muonic molecule, potentially displacing the original electron:

    H - μ - H

    Due to the high mass of the muon, the bond-length of the molecule shrinks drastically, providing a proton/deuteron/triton to proton/deuteron/triton separation of approximately 0.5 picometers (5x10^-13 m), allowing fusion to occur via tunnelling at room temperatures and lower.

    Unfortunately, the catch is that the muon is short-lived and costs more energy to make than it can generate through this process and can "stick" to the resulting helium nucleus. As a chemist, this is of no surprise, naked helium has a much higher total ionization energy than hydrogen (atomic or molecular).

    As an aside - I'm wondering if perhaps flooding your muon-fusion reactor with IR or UV radiation appropriate to the stretching frequency He-μ bond interaction would help muon catalysis turnover, although I don't know what effect that would have on theoretical energy balance.

    My main question is whether this would work with a supersymmetric electron - the selectron?

    I haven't been able to find a range for the predicted mass of a selectron, but I'm guessing it is very high indeed, and would allow this process to happen readily. Furthermore, the selectron would presumable be stable, allowing for room temperature fusion to be easily harnessed (at only the cost of keeping the resulting selectron-helium atoms ionised, which may be a deal-breaker, depending on the strength of the interaction).

    So the question is - does anyone know what kind of mass range the selectron, if it exists, would be expected to have?
    Would the selectron be stable?
    Is there any reason selectron-catalysed fusion a-la muon-catalysed fusion wouldn't work?
  2. jcsd
  3. Sep 3, 2012 #2


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    The only strong motivation for supersymmetry is if it occurs at the electroweak unification energy. This is the energy range that the LHC was designed to probe, and it hasn't seen any SUSY particles. This probably indicates that SUSY doesn't exist, and it definitely puts a lower mass limit on the lightest superpartners which is on the order of the electroweak unification energy.

    Even if selectrons exist, they're definitely not stable. From googling, it looks like the main decay mode is expected to be into an electron plus a neutralino.
  4. Sep 3, 2012 #3
    That's not too surprising. I still think they would work for this process in principle but wouldn't have long enough lifetimes and far too high an energy cost to be useful.

    Here's hoping something may come from muon-catalysed and thermo-fusion!
  5. Sep 4, 2012 #4


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    If there are stable SUSY particles, they have to be uncharged (both electric and color), otherwise we would see them everywhere.
    SUSY particles with the usual concepts (if they exist at all) have to be heavy and most (all?) unstable of them are expected to be very short-living compared to muons. In addition, they require really large accelerators to be produced, and have an extremely small cross-section. To make things worse, they are produced with high energy (that could be partially fixed with electron/positron accelerators) and would have to be slowed down first.

    The muon/helium binding energy is ~10keV, you would need x-rays and a good conversion efficiency.
  6. Sep 4, 2012 #5
    I think there might actually be some exotic scenarios which predict quite long lived charged particles. I don't remember if any of them predict "long" as being longer than the muon lifetime though...
  7. Sep 4, 2012 #6


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    Well, you have to be careful with "long-living". For particle physicists, a picoseconds is enough for "long-living", as you can see the flight distance in the detectors. Muons are "stable" in the sense that they usually do not decay during their flight through particle detectors.
  8. Sep 7, 2012 #7
    I suppose that is tiberium.
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