Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Strings as preons: does string theory allow muons to decay directly into e- + y

  1. Oct 10, 2006 #1
    strings as preons: does string theory allow muons to decay directly into e- + photon, given that the only difference between an electron and a muon, in string theory, is the string's tension? Of course, that's not how muons decay, (they decay into a W- boson, which decays into an electron and electron neutrino) but in string theory, all particles of the standard model are just different frequencies of one fundamental string. Graphically, it's not all that much different than Bilson's ribbon model, where all particles are made of braiding of a ribbon. In strings, all particles of the standard model are made of one string, whose frequency (tension) differs.

    If string theory is unable to prevent muons from decaying directly into electrons and photons, in contradiction to observation, doesn't this provide evidence that string theory is false?

    String theory has always struck me as a kind of preon theory.

    would string theory suffer from many of the problems preons theory have, including mass paradox and t'Hooft anomy matching?

    However string theory explains the decay of a fundamental string of a muon into a W- boson, rather than directly into an electron and photon, could that explanation be used for preon theory? However string theory gets around mass paradox or t'Hooft anomly matching, could those explanations be applied to proposed preon models?
     
  2. jcsd
  3. Oct 11, 2006 #2

    arivero

    User Avatar
    Gold Member

    I do not know how do the particles appear in the string model, but I am almost sure it is not about frequencies. Anyone willing to explain?
     
  4. Oct 11, 2006 #3

    selfAdjoint

    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed


    Ah, but it is. The particle spectrum of the string is constructed from the normal modes of its vibration. And normal modes are a set of "pure frequencies" of a quantum oscillator, which can be used to generate the given vibration.
     
  5. Oct 11, 2006 #4
    If string theory is unable to prevent muons from decaying directly into electrons and photons, in contradiction to observation, doesn't this provide evidence that string theory is false?
     
  6. Oct 11, 2006 #5

    selfAdjoint

    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    Certainly not all string models of low energy physics obey this. Some of them have the strings wrapped n times around some arm of a C-Y manifold for the different generations, which would preclude the decay you mention, and others would regard different low energy particles as different strings spanning two (possibly different) branes. I don't know the details of any of this; Zuebach's book hs an example of one such model. But the simple model you quote is probably only some oversimplification from a popularized book.
     
  7. Oct 12, 2006 #6

    arivero

    User Avatar
    Gold Member

    So it is not about frequencies in a fundamental way.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Strings as preons: does string theory allow muons to decay directly into e- + y
Loading...