: any of a family of particles (such as electrons, muons, and neutrinos) that have spin quantum number ¹/₂ and that experience no strong forces
Examples of lepton in a Sentence
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Ethan Siegel, Big Think, 9 Sep. 2025
But nothing ever seems to stick, and that's because no experiment has given any hint that quarks and leptons are composite particles.
—Paul Sutter, Space.com, 24 Dec. 2024
By 1967, Steve Weinberg had extended the Higgs mechanism to account for the mass of electrons and heavier leptons, and in 1971, Gerard ‘t Hooft and Martinus Veltman figured out how to get rid of a few annoying infinities in some of the equations.
—Jennifer Ouellette, Ars Technica, 9 Apr. 2024
Their efforts have led to the Standard Model of particle physics, which describes the most fundamental ingredients of matter (leptons and quarks) and the forces that control them (the electromagnetic, strong and weak forces).
—Daniel Garisto, Scientific American, 13 Dec. 2023
The more exotic possibility is that LHCb researchers are detecting hints of a fabled particle — the leptoquark — that can turn a quark into a lepton and vice versa.
—Quanta Magazine, 26 May 2020
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Noun
But for the neutrinos — the uncharged leptons — their status as a spin-½ particle is a little different.
—Ethan Siegel, Big Think, 9 Sep. 2025
But nothing ever seems to stick, and that's because no experiment has given any hint that quarks and leptons are composite particles.
—Paul Sutter, Space.com, 24 Dec. 2024
By 1967, Steve Weinberg had extended the Higgs mechanism to account for the mass of electrons and heavier leptons, and in 1971, Gerard ‘t Hooft and Martinus Veltman figured out how to get rid of a few annoying infinities in some of the equations.
—Jennifer Ouellette, Ars Technica, 9 Apr. 2024
Their efforts have led to the Standard Model of particle physics, which describes the most fundamental ingredients of matter (leptons and quarks) and the forces that control them (the electromagnetic, strong and weak forces).
—Daniel Garisto, Scientific American, 13 Dec. 2023
The more exotic possibility is that LHCb researchers are detecting hints of a fabled particle — the leptoquark — that can turn a quark into a lepton and vice versa.
—Quanta Magazine, 26 May 2020
Cite this Entry
“Lepton.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lepton. Accessed 31 Oct. 2025.
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