pion
[ pahy-on ]
/ ˈpaɪ ɒn /
noun Physics.
the first meson to be discovered: it has spin 0 and may be positively or negatively charged or neutral; charged pions decay into a muon and a neutrino or antineutrino. Symbol: π
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Also called pi meson.
Origin of pion
First recorded in 1950–55; pi (meson) + -on1
Words nearby pion
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020
Example sentences from the Web for pion
British Dictionary definitions for pion
pion
pi meson
/ (ˈpaɪɒn) /
noun
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
Word Origin for pion
C20: from Greek letter pi 1 + on
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Scientific definitions for pion
pion
[ pī′ŏn′ ]
A meson occurring either in a neutral form with a mass 264 times that of an electron and a mean lifetime of 8.4 X 10-17 seconds or in a positively or negatively charged form with a mass 273 times that of an electron and a mean lifetime of 2.6 X 10-8 seconds. The pion was once believed to be the particle that mediates the strong force, which holds nucleons together in the nucleus; it is now believed that the gluon is the mediator particle. Pions do interact with nucleons, however, and are able to transform neutrons into protons and vice versa. Also called pi-meson See Table at subatomic particle.
The American Heritage® Science Dictionary
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