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magnified atoms - looks like an uneven black and white and gray waffled surface

A meson is much smaller than an atom! These are lithium, cobalt, and oxygen atoms (as in a lithium-ion battery), seen under an electron microscope from Berkeley Labs.

What is a meson?

Mesons are tiny sub-atomic particles. Sub-atomic means they are smaller than atoms. They form out of quarks in high-energy situations.

More about atoms
What are quarks?
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How big is a meson?

Mesons are about 2/3 the size of protons or neutrons. A meson is a kind of boson. Mesons are too small for us to see directly. Physicists only know they are there because of how they affect bigger things that we can see. It’s like when you know your sister messed up your room, even though she isn’t there anymore, because you can see the things she moved around.

What are protons and bosons?
And what are neutrons?

How long do mesons hang around?

All mesons are unstable: they form and break up again in less than a few hundredths of a microsecond. (And a microsecond is only one millionth of a second!) Mesons with an electrical charge decay into electrons and neutrinos; mesons without any electrical charge can decay into photons.

What are photons?

Did you find out what you wanted to know about mesons? Let us know in the comments!

More about electrons

More about quarks

Bibliography and further reading about mesons and atoms:

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