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Muonic atoms
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Muon replaces an electron, shrinking the orbit.
A muon (207 times heavier) replaces the electron, orbiting 207 times closer, probing nuclear size; also used in muon-catalysed fusion.
Muonic hydrogen revealed a smaller proton radius.
Muons decay in 2.2 μs.
In more detail
Muonic atoms contain a muon instead of an electron. Because the muon is about 200 times heavier, its orbit is much closer to the nucleus, giving a sensitive probe of nuclear size.
Real-world uses
- Muonic X-rays measure nuclear radii precisely.
- Muon spectroscopy tests quantum electrodynamics.
- Researchers use muonic atoms to measure the size of nuclei with greater precision than with electrons.
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Frequently asked questions
What is a muon?
A heavy cousin of the electron with a short lifetime of about 2.2 microseconds.
Why use muons to measure nuclei?
Their closer orbit probes the nucleus more directly.
Why does a muon shrink the orbit?
The muon is about 200 times heavier than the electron, so its orbit is much closer to the nucleus.
Related topics in Atomic & Nuclear Physics
Nuclear waste · Hydrogen-like ions · Positronium · Atomic clocks · Laser cooling of atoms