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Thread: Why do WIMPs annihilate each other when they collide?

  1. #1
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    Why do WIMPs annihilate each other when they collide?

    They can't have an electric charge, or they'd emit electromagnetic radiation, so what causes them to destroy each other?
    "Occam" is the name of the alien race that will enslave us all eventually. And they've got razors for hands. I don't know if that's true but it seems like the simplest answer."

    Stephen Colbert.

  2. #2
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    Quote Originally Posted by parallaxicality View Post
    They can't have an electric charge, or they'd emit electromagnetic radiation, so what causes them to destroy each other?
    Opposite weak isospin.

    Grant Hutchison

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    Just to clarify to anyone reading this thread, WIMPs have not been observed. Grant is correct IF WIMPs exist at all. If dark matter is made of particles which do not interact with the weak force, then they aren't WIMPs, and need to be called something else. Current searches for dark matter as a particle are mostly looking for WIMPs, though Axions, Sterile Neutrinos, and other forms are also being searched for.
    Forming opinions as we speak

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    Wait so, WIMPs are Weakly Interacting Massive Particles because they interact with the weak force, not because they interact weakly?
    "Occam" is the name of the alien race that will enslave us all eventually. And they've got razors for hands. I don't know if that's true but it seems like the simplest answer."

    Stephen Colbert.

  5. #5
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    Quote Originally Posted by parallaxicality View Post
    Wait so, WIMPs are Weakly Interacting Massive Particles because they interact with the weak force, not because they interact weakly?
    That's one definition, and the one, I think, that allows predictions about how to detect WIMP annihilations - see the discussion at Fermilab, for instance.

    There's a broader definition that also includes the possibility of interaction via some other, currently unknown force, as weak as the weak force. In which case that force will presumably be associated with a conserved quantity analogous to charge or isospin, which will allow the existence of particles and antiparticles with opposite values that cancel out in an annihilation.

    Grant Hutchison

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    Why doesn´t world simply have a conserved wimp number preventing wimps from having anything to annihilate with, much like world has a conserved and large baryon number and conserved but totally unknown lepton number?

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    Quote Originally Posted by chornedsnorkack View Post
    Why doesn´t world simply have a conserved wimp number preventing wimps from having anything to annihilate with...
    Perhaps they are bosons, or perhaps they are unlike anything else we've ever detected.
    Forming opinions as we speak

  8. #8
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    And, as discussed in my Fermilab link above, the primary reason we talk about hypothetical WIMPs that can annihilate each other is because those hypothetical WIMPs can be detected more easily than any hypothetical WIMPs that don't annihilate each other.

    Grant Hutchison

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