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Where are the other quarks?

  1. Oct 10, 2015 #1
    Hello, everybody. I have a question that is really confusing me: how can they find charm, strange, top, and bottom quarks? They are in the 2nd and 3rd generations, so they are more unstable than the first generation up and down quarks, and unlike them, they are not found in protons or neutrons. So are there presence theoretical, or am I missing something?
     
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  3. Oct 10, 2015 #2

    Orodruin

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    You can create the heavy quarks in particle collisions. They decay quickly and are not found occuring naturally except in high energy processes.
     
  4. Oct 10, 2015 #3
    Which particle collisions? Did they do this in the large hadron collider?
     
  5. Oct 10, 2015 #4

    ChrisVer

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    LHC is not the only collider. There have been for example electron-positron colliders.

    Bottom was discovered at Fermilab. Similarily for top (the hardest there was). Another example for charm, its discovery happened at SLAC by observing the J/psi resonance. This was an electron positron accelerator.
     
  6. Oct 10, 2015 #5

    jtbell

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    This was in the mid 1970s. Going back further, the first "strange" particles, the K mesons, were discovered in interactions of cosmic rays in cloud chambers, in the late 1940s. The original quark model with up, down and strange quarks came in the 1960s.
     
  7. Oct 11, 2015 #6

    mfb

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    Protons and neutrons have small contributions from those quarks. In addition to the valence quarks (2 up 1 down or 1 up 2 down), there are sea quarks. This quark contribution can be studied.
    The main production mode of heavy quarks is pair production, however: the heavy quarks get created in the collision process, one quark and one antiquark at the same time.
     
  8. Oct 11, 2015 #7

    ChrisVer

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    I've only seen up to strange quarks....
     
  9. Oct 11, 2015 #8

    mfb

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    The contributions from charm and bottom are smaller as they have a larger mass, but they exist.
    http://lhc.fuw.edu.pl/Stirling.pdf [Broken]
    Slides 55+

    Photon + heavy flavor jet is a nice way to measure them.
    W plus top or strange is another option, but W+top probably has a large experimental background from top antitop production and W+strange has up+gluon -> W+strange as irreducible background process.
     
    Last edited by a moderator: May 7, 2017
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