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A Proton

Protons are positively charged particles found within atomic nuclei. Protons were discovered by Ernest Rutherford in experiments conducted between the years 1911 and 1919.

Experiments done at the Stanford Linear Accelerator Center in the late 1960's and early 1970's showed that protons are made from other particles called quarks. Protons are made from two 'up' quarks and one 'down' quark.

Particle Data

SymbolMassHalf-lifeChargeSpinQuark Content
p938.3 MeV>1032 years+11/2uud

Citation and linking information

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