quarks

Discussion in 'Physics & Math' started by timojin, Oct 11, 2017.

  1. timojin Valued Senior Member

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    What is a lifespan of quarks,
    what will the temperature necessary to maintain them from forming protons or neutrons
     
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  3. timojin Valued Senior Member

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    Are there any physicist that might stretch his hand out ?
     
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  5. exchemist Valued Senior Member

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    According to my very limited understanding of particle physics, you need a temperature around 2 x 10¹²K to sustain a quark/gluon plasma.

    Up and Down quarks are I think stable, but the other quarks can change into one another under various conditions. I don't know the details, I'm afraid. I expect someone else can tell you more.
     
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  7. arfa brane call me arf Valued Senior Member

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    Nope. No particle is stable given enough energy.
     
  8. exchemist Valued Senior Member

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    Fair enough. What would happen to an Up or Down quark?
     
  9. arfa brane call me arf Valued Senior Member

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    There are Feynman rules for the decay of quarks, I think. As for any particles.
     
  10. exchemist Valued Senior Member

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    What would those rules indicate in this case?
     
  11. arfa brane call me arf Valued Senior Member

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    Top quarks decay spontaneously because the universe has a much lower energy density today than when top quarks didn't decay often . . . ?

    You have Feynman rules for up quarks decaying to down quarks and vice-versa. You still have one quark in, one out, but you also get decay products, e.g. photons.
     
  12. exchemist Valued Senior Member

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    So Up and Down quarks decay into each other, with loss of some energy as photons? Is that right?
     
  13. timojin Valued Senior Member

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    If I understand you can rise the temperature for short period of time but as the temp. drops from the excitation it falls back to its stable state. As in the CERN experiment , due to collision quarks were produced but they were not able to separate them . So did they collapse into protons or some formed a heavy quarck
    of a mass of tungsten ?
     
  14. arfa brane call me arf Valued Senior Member

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    I note there's a difference (possibly arbitrary) between spontaneous decay and scattering. The latter is what the LHC does--scatter protons off protons.
    But, the detectors detect decay products.

    I suppose I can say (since I'm not a particle physicist), that protons decay spontaneously into decay products of various types, when they scatter off each other with sufficient energy.

    Maybe someone should email a relevant question to an actual physicist who knows more about it.
     

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