# Thread: Smallest matter in existence

1. I'd go with what Keith said. Neutrinos are extremely small and aren't affected by the electromagnetic force. They could go through a light year of lead without interacting with anything. But, like Keith said, they cannot assemble into matter.

Quarks can only be found in baryons (protons and neutrons) and mesons (one quark, one anti-quark). However, if the tempratures are extreme enough, there could be a quark-gluon plasma where the quarks and gluons flow freely, moving too fast to affect one another. Only in this plasma can a quark be found by itself. These temperatures only existed in nature during certain stages of the big bang. Phyicists have also been able to recreate these conditions in particle accelerators.

Since quarks and gluons are bulding blocks of matter they may not be considered matter by themselves. I'm not really sure. If that's the case then the proton may be the smallest form of matter.

2. Only in this plasma can a quark be found by itself
Lost and alone amongst so many. Poor lonely Quark. Like the last cilia in a smoker's lungs...

3. 1 eV = 1.602e-19 joules (joules/c^2 = kg)

Neutron mass- 939.566 MeV/c^2 (1.675e-27 kg)

Up quark mass- ~2.4 MeV/c^2 (1.5 - 3.3)

Down quark mass- ~4.75 MeV/c^2 (3.5 - 6.0)

energy unaccounted for by (rest) mass- 940 - (2 x 4.75 + 2.4) â‰ˆ 928 MeV/c^2

based on three gluons existing at any one time within a brayon-

928/3 = ~gluon energy (~309 MeV)

But if we have more gluons energy should be less.

Radius (or wavelength lambda) can be estimated as lambda = h c/energy

For gluon it is 4.013e-15 m. So we still can go to smaller (compare with plank length)
Last edited by astroval; 05-17-2011 at 02:40 AM.

4. Originally Posted by nasgath
there must be a last internal structure of the atom, shouldn't there be one?
Why must there be?

Every time in the past that people thought they had found the "fundamental particles of matter", they were wrong. There isn't any reason to think that a particular particle is fundamental except that we have not seen its internal structure. Yet.

When I was in school, protons and neutrons were considered to be fundamental particles. Not any more.

Maybe there are fundamental particles; maybe there aren't. If there are, maybe we have found some of them; maybe we haven't. We simply do not have any information one way or another. In fact it is hard to see how such information could ever be determined.

5. ## The Following 5 Users Say Thank You to KathyNS For This Useful Post:

astroval (05-17-2011),chas53 (05-17-2011),Cladinator (05-17-2011),j.gardavsky (05-17-2011),samgray1 (05-17-2011)

6. Fundamental matter? Or waves? Perhaps you can say that there's a smallest type of matter (perhaps it is the atom even), and after that you get into wave/particle land.

7. Any matter has wavelength. See matter waves. Such Wave–particle duality of matter were demonstrated in Double-slit experiments and show Particle diffraction.

Recent studies have found that even large (compared to protons, etc.) objects as molecular structures like fullerene with 60 atoms (C60) were also shown to diffract.

So wave/particle land works on any scale.

8. The straange thing about the wave/particle duality is that although the particle appears to have a wave-like behavior, it doesn't. It just APPEARS to have this wave-like quality. Its complicated and I read it in a Feynman lecture, but it can all be explained with quantum mechanics. Such amazing stuff.

9. Oh, I just realized what the experiments at LHC are about:

"The Large Hadron Collider (LHC) is a gigantic scientific instrument near Geneva, where it spans the border between Switzerland and France about 100 m underground. It is a particle accelerator used by physicists to study the smallest known particles â€“ the fundamental building blocks of all things. It will revolutionise our understanding, from the minuscule world deep within atoms to the vastness of the Universe."

So basically they are trying to get the same answer to my question on this thread . What are your thoughts on the outcome results of LHC experiments? Do you think they hold the key to the/a breakthrough of the century? Cheers.

- T

10. Originally Posted by nasgath
What are your thoughts on the outcome results of LHC experiments? Do you think they hold the key to the/a breakthrough of the century?
That is going to depend very much on whether they get results.

11. Smallest matter in existence
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