20 lines
1.1 KiB
HTML
20 lines
1.1 KiB
HTML
<h1>The Three Generations of Matter</h1>
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<p class="abstract">So far we have met the particles that make up most
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of the matter we see all around us - the up quark, the down quark and
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the electron. We have also met the electron neutrino, which is emitted
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during radioactive decay. It seems like these four particles, along
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with the particles that carry forces, are enough to explain
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everything.</p>
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<p class="abstract">It turns out that each of the matter particles has
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two "big brothers" - new particles that are identical except for their
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larger mass. Physicists talk about "three generations" (sometimes
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called families instead) of matter. The first generation is the
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particles we have met already. The second generation contains the
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charm quark (the big brother of the up quark), the strange quark (the
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big brother of the down quark), the muon (the big brother of the
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electron) and the muon neutrino (the big brother of the electron
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neutrino). The third generation is the top quark, the bottom quark
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(this is sometimes also called the beauty quark), the tau lepton and
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the tau neutrino.</p>
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