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Bogie
2008-Apr-23, 07:49 PM
We have evidence that protons are composed of three quarks based on accelerator experiments where collisions destroy protons and quarks have been identified in the debris.

Do we have evidence that three quarks from such collisions have joined to form a proton? I would like a link that discusses the evidence to support proton formation from quarks.

alainprice
2008-Apr-23, 09:03 PM
There are no free quarks that I know of, so how do you expect quarks to 'form' a fresh proton?

Bogie
2008-Apr-23, 09:26 PM
There are no free quarks that I know of, so how do you expect quarks to 'form' a fresh proton?I don't expect it. I was asking. Quarks are identified by accelerator experiments aren't they. If a stream of protons are collided wouldn't there be a cloud containing various quarks in an environment where they could form a proton right before our eyes? I'm asking if this has been observed.

blueshift
2008-Apr-23, 11:51 PM
I don't expect it. I was asking. Quarks are identified by accelerator experiments aren't they. If a stream of protons are collided wouldn't there be a cloud containing various quarks in an environment where they could form a proton right before our eyes? I'm asking if this has been observed.What has been observed is called Inelastic Scattering. By taking an electron beam and firing it into a meson, akin to Rutherford's experiment with a gold foil, the electron beam stretched the gluon field until it snapped, causing the amount of energy used to convert to a new quark/antiquark pair. The result made scientists realize that they cannot separate quark pairs without creating new ones. Quarks cannot be isolated. They also realized that gluon fields disobey the inverse square law, they become stronger with distance.

So they didn't identify the quarks directly. They identified the result of two mesons existing where one was prior to beam bombardment. Stretching the fields more and more produced more and more mesons.

Bogie
2008-Apr-24, 12:13 AM
What has been observed is called Inelastic Scattering. By taking an electron beam and firing it into a meson, akin to Rutherford's experiment with a gold foil, the electron beam stretched the gluon field until it snapped, causing the amount of energy used to convert to a new quark/antiquark pair. The result made scientists realize that they cannot separate quark pairs without creating new ones. Quarks cannot be isolated. They also realized that gluon fields disobey the inverse square law, they become stronger with distance.

So they didn't identify the quarks directly. They identified the result of two mesons existing where one was prior to beam bombardment. Stretching the fields more and more produced more and more mesons.Thanks Blueshift for that explanation. I found it helpful.