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Quarks and proton?

  1. Jun 17, 2015 #1


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    I read some time ago there are many more as 3 quarks in proton but lot of publications mention only 3 quarks!
    Where is the truth?
  2. jcsd
  3. Jun 17, 2015 #2
    It's 3 and is always 3.
  4. Jun 17, 2015 #3
    There are only 3 quarks in a proton. Maybe you read about the force particles that keep them together (gluons).
  5. Jun 17, 2015 #4


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    The truth here is that we don't know what you read, and if you read something silly, or you misinterpret what you read.

    In this forum, always cite your source! Otherwise, we can't really figure out where the problem is.

    There are a total of 6 different types of quarks in the Standard Model of particle physics. There are two different types of quarks in a proton, but there are three of them - uud.

  6. Jun 17, 2015 #5


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  7. Jun 17, 2015 #6


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    I put this question because of this article from Theoretical Physicist Matt Strassler:
    You may have heard that a proton is made from three quarks. Indeed here are several pages that say so. This is a lie — a white lie, but a bigone. In fact there are zillions of gluons, antiquarks, and quarks in a proton. The standard shorthand, “the proton is made from two up quarks and one down quark”, is really a statement that the proton has two more up quarks than up antiquarks, and one more down quark than down antiquarks. To make the glib shorthandcorrect you need to add the phrase “plus zillions of gluons and zillions of quark-antiquark pairs.”Without this phrase, one’s view of the proton is so simplistic that it is not possible to understand the LHC at all.


    Any comment?
  8. Jun 17, 2015 #7


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    This happens a lot when you read pop-sci explanations. Yes, when we say that there are exactly three quarks in a nucleon, that's a white lie... but then again, when we say that that the earth is round, that's also a white lie because it's really kind of slightly pear-shaped.

    Strassler is trying to say that there's a lot of complicated physics and subtle nuance behind the simple statement that there are three quarks in a nucleon, just as there's a lot of complicated physics and subtle nuance behind the simple statement that the earth is round. He's right about that, but he's chosen a rather unfortunate way of making this point.
  9. Jun 17, 2015 #8
    Just so i understand the Strassler guy's point, is he alluding to the myriad "higher-order" interactions (i.e. with virtual pairs) one has to consider in QCD when calculating the strength of the interactions?
  10. Jun 17, 2015 #9


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    That's what I think he's alluding to yes. This is what people mean when they talk about "the strange quark content of protons", for instance. http://www.symmetrymagazine.org/breaking/2010/04/27/protons-not-as-strange-as-expected
  11. Jun 18, 2015 #10
    Wow, that is a terrible way of getting that subtlety across. Strassler probably thinks he educated the reader more, but this is a classic example where badly placed additional information can cause greater harm than not mentioning it. Kinda like that guy a while ago who insisted on bringing relativity into the picture for a total bare-bones physics question.
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