down quark

American  

noun

Physics.

1. the quark having electric charge −1/3 times the elementary charge, with strangeness, charm, and other quark quantum numbers equal to 0.

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Etymology

Origin of down quark

First recorded in 1975–80

Example Sentences

See Examples For:

down quark

While a proton contains two up quarks and one down quark, the Ξcc⁺ replaces the up quarks with heavier charm quarks.

From Science Daily ● Mar. 19, 2026

Normal protons have two "up" quarks and one "down" quark.

From Barron's ● Mar. 17, 2026

Physicists are also reassessing particle flavor, a quantum property that defines the species of fermion: up quark, down quark, electron, muon, and so on.

From Scientific American ● Sep. 8, 2022

Dr. Spradlin said he and his colleagues are searching the same data that revealed the Xi-cc++ for the baryon with two charm quarks and one down quark.

From New York Times ● Jul. 6, 2017

A proton contains two up quarks and one down quark; a neutron contains two down and one up.

From "A Brief History of Time: And Other Essays" by Stephen Hawking