pion

noun

pi·​on ˈpī-ˌän How to pronounce pion (audio)
: a meson that is a combination of up and down quarks and antiquarks, that may be positive, negative, or neutral, and that has a mass about 270 times that of the electron
pionic adjective

Examples of pion in a Sentence

Recent Examples on the Web Above, the top picture (from a later experiment) shows an example of the antiproton (the pale blue streak) annihilating a proton and creating positive and negative particles known as pions (respectively, the red and green lines). Discover Magazine, 1 Sep. 2010 Beams of energy collide with atoms in Earth’s upper atmosphere, spawning charged subatomic particles like pions, muons, electrons, and positrons, whose ionized trails show up as spindly lines in cloud chambers. Bill Gourgey, Popular Science, 23 Nov. 2023 Instead, at these scales, a new effective force emerges—the strong nuclear force, transmitted between nucleons by the exchange of pions. WIRED, 10 Aug. 2023 The positive pion can interfere with other positive pions caused by other atomic flybys. Stephanie Pappas, Scientific American, 11 Jan. 2023 Instead, at these scales, a new effective force emerges — the strong nuclear force, transmitted between nucleons by the exchange of pions. Katie McCormick, Quanta Magazine, 12 June 2023 Recently, for instance, LHCb (one of the experiments at the LHC) measured the decays of certain unstable composite particles similar to pions that produce either muons or electrons. Marcela Carena, Scientific American, 1 Oct. 2021 This process produces pions, unstable composite particles that then decay into neutrinos and muons through weak force effects. Marcela Carena, Scientific American, 1 Oct. 2021 For example, in the 1960s physicists noticed a discrepancy in the decay rate of a particle called the pion. Kevin Hartnett, Quanta Magazine, 18 Apr. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'pion.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

contraction of pi-meson

First Known Use

1950, in the meaning defined above

Time Traveler
The first known use of pion was in 1950

Dictionary Entries Near pion

Cite this Entry

“Pion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pion. Accessed 19 Mar. 2024.

Last Updated: - Updated example sentences
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