- 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
Origin of pion
Also called pi meson.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for pion
Do not forget next week at the home of Endora, on the Mountain of Pion.Saronia
I refer to the pion pine, of which there are several species.North America
Israel C. Russell
But he turned and scrambled up a rocky bank into the pion woods that border the benches of the Meteetsee.The Biography of a Grizzly
This heres the Wagon Tire House, returned its proprietor, rising and shaking the pion slivers from her checked apron.
The dense forest consists of pion pine, juniper, Douglas fir, and western yellow pine.Mesa Verde National Park, Colorado
- 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 pi 1 + on
Word Origin and History for pion
Online Etymology Dictionary, © 2010 Douglas Harper
- 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 Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.