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Q & A: Any elementary particles in the body?

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Most recent answer: 01/24/2014
Hi I am trying to figure out what the body is made of, down to the elementary particles. I am just wondering if anti-matter exists in the human body? I usually find the answer to every question just googling it, but with this question i couldn't. The only thing i found out about this question was that potassium 40 from things we eat or drink decays and produces positrons in our body.
- Marc Crowner (age 24)
United States

Hello Mark,

The overwhelming particle constituents of the body are electrons, protons, and neutrons.  They are usually combined in the form of neutral atoms.  As you point out there are trace elements that are radioactive such as Potassium 40 and the occasional Uranium 238 and Thorium 232.   You can find a complete list at: .  One of the decay modes of Potassium 40 is Calcium plus an positron and a neutrino.  The neutrino will escape the body immediately but the positron will slow down and be captured by an electron and then this pair will annihilate into two or three gamma rays, so you wind up with no anti-matter.




(published on 01/24/2014)

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