# References on the non-compositeness of the known elementary particles

What paper(s) or theory(s) describe or prove that the elementary particles that we have determined today cannot be made up of smaller more fundamental particles?

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+1 Nice question, but the title is a bit uninformative. I made a suggestion (but feel free to pick your own) –  Tobias Kienzler Mar 21 '11 at 9:05
Many papers proceed from an idea of particle being point-like, and what can be even smaller? ;-) –  Vladimir Kalitvianski Mar 21 '11 at 9:31
I don't think there can be such a proof, ever. The reason is that there is no (experimental) distinction between "very tiny" and point-like. That's why we still often treat atoms as non-composite when dealing with them at larger scales (or even forget there are any atoms altogether...). –  Marek Mar 21 '11 at 9:53
it may very well be that there is no limit to the true levels of substructure of elementary particles. However, what is becoming clearer, and what I believe, is that for explaining natural phenomena it is not the irreducible properties of elementary particles that matter as much as the emergent properties of aggregates of many such particles interacting in many-body systems. –  user346 Mar 27 '11 at 6:36
Also the question of whether there exists an irreducible description - in the reductionist sense - of matter becomes unclear in light of the mutable nature of particles as revealed by phenomena such as bosonization (fermionization) and fractionalization which are found in lower-dimensional condensed matter systems. –  user346 Mar 27 '11 at 6:37

One of the questions under investigation in the data being gathered at LHC is the search for compositeness of quarks and leptons. They gave limits for quark compositeness from the data of 2010.

So the answer is, it is an open question under investigation, though not popular with the theorists.

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There is no such theory. We treat the elementary particles as elementary simply because we have never seen any evidence of them having a substructure.

I suppose someone might have published a paper claiming that they must be fundamental (after all, there are a lot of papers out there), but the vast majority of physicists do not take such claims seriously.

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