What's a meson?

[dstebbins]

As you can see, I just got to the rank of Meson. What is a meson in the scientific world? I knew what a quark was, but not a meson.

[ydoaPs]

In particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin. In the Standard Model, mesons are composite (non-elementary) particles composed of an even number of quarks and antiquarks. All known mesons are believed to consist of a quark-antiquark pair — the so-called valence quarks — plus a "sea" of virtual quark-antiquark pairs and virtual gluons. Searches for exotic mesons that have different constituents are ongoing. The valence quarks may exist in a superposition of flavor states; for example, the neutral pion is neither an up-antiup pair nor a down-antidown pair, but an equal superposition of both. Pseudoscalar mesons (spin 0) have the lowest rest energy, where the quark and antiquark have opposite spin, and then the vector mesons (spin 1), where the quark and antiquark have parallel spin. Both come in higher-energy versions where the spin is augmented by orbital angular momentum. All mesons are unstable.

 

Mesons were originally predicted as carriers of the force that binds protons and neutrons together. When first discovered, the muon was identified with this family from its similar mass and was named "mu meson", however it did not show a strong attraction to nuclear matter and is actually a lepton. The pion was the first true meson to be discovered. (The current picture of intranuclear forces is quite complicated; see quantum hadrodynamics for a discussion of modern theories in which nucleon-nucleon interactions are mediated by meson exchange.)

 

In 1949 Hideki Yukawa was awarded the Nobel Prize in Physics for predicting the existence of the meson. He originally named it 'mesotron', but was corrected by Werner Heisenberg (whose father was a professor in Greek at University of Munich) that there is no 'tr' in the Greek word 'mesos'.

 

Go Go Gadget Wikipedia

[dstebbins]

okay, you're just confusing me further. Lepton? Muon? Pion? Wtf?

[timo]

I knew what a quark was, but not a meson.

Two quarks . Next rank is baryon, three quarks, I think.

[alan2here]

Quark --> Meson --> Baryon --> [some more stuff] --> Primate --> [some more Stuff] --> Scientist\[subject] Expert?

[timo]

I knew there´s a thread listing the normal user titles somewhere around: http://www.scienceforums.net/forum/showthread.php?t=127&highlight=user+title

 

Titles (or silly descriptions) not in that list are a hint on someone with a custom user title i.e. either admin, moderator or expert.