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Any of the three least massive mesons, having a positive, neutral, or negative electric charge. The charged pions have a mass 273 times that of an electron and a mean lifetime of 2.6 × 10-8 second, and the neutral pion has a mass 264 times that of an electron and a mean lifetime of 8.4 × 10-17 second. Also called pi meson.

[Contraction of pi meson.]


(ˈpaɪɒn) or

pi meson

(General Physics) physics a meson having a positive or negative charge and a rest mass 273.13 times that of the electron, or no charge and a rest mass 264.14 times that of the electron
[C20: from Greek letter pi1 + on]


(ˈpaɪ ɒn)

any of the three lightest mesons, having positive, negative, or neutral electric charge and spin of zero.
[1950–55; pi (meson) + -on1]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.pion - a meson involved in holding the nucleus together; produced as the result of high-energy particle collision
meson, mesotron - an elementary particle responsible for the forces in the atomic nucleus; a hadron with a baryon number of 0
References in periodicals archive ?
So, while the DZero collaboration spotted an excess 133 pairs of BS mesons and pi mesons - produced when X(5568) decays - the CERN scientists spotted none.
These pi mesons interact with the neutrons and protons to heat the nucleus rapidly from the inside, pushing temperatures as high as 20 billion kelvins.
Pions, also known as pi mesons, are the lightest charged particles used in these radiation trials.