Where Are the Missing Quarks in Particle Physics?

[BluberryPi]

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?

 

[Orodruin]

You can create the heavy quarks in particle collisions. They decay quickly and are not found occurring naturally except in high energy processes.

 

[BluberryPi]

Which particle collisions? Did they do this in the large hadron collider?

 

[ChrisVer]

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.

 

[jtbell]

Another example for charm, its discovery happened at SLAC by observing the J/psi resonance.

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.

 

[mfb]

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.

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.

 

[ChrisVer]

This quark contribution can be studied.

I've only seen up to strange quarks...

 

[mfb]

I've only seen up to strange quarks...

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