How To Use Down quark In A Sentence

A neutral pion consists of a down quark and a down antiquark.
A free neutron, for example, will decay with a half-life of about 18 minutes into a proton, electron and antielectron-neutrino, due to a down quark decaying into an up quark via the emission of a virtual W- particle. Your Favorite Conservatives on Evolution and ID - The Panda's Thumb
The wave functions of both the deuteron and the alpha particle are invariant under the interchange of up and down quarks but recall that the pion wave function is not.
Now nuclear physicists in Japan, Russia and the US have discovered a particle that contains two up quarks, two down quarks and a strange antiquark.
A neutral pion consists of a down quark and a down antiquark.

At this energy level, only up and down quarks, the electron and the electron neutrino exist.
The new results promise to yield important information about the up and down quarks that comprise protons and neutrons.
Quarks come in oddly named ‘flavors,’ and all the new species include two strange, one anti-up, and either an up or a down quark among the five (the pentaquarks discovered last spring all had two ups, two downs, and one anti-strange).
Everyday matter is composed of just three types of particles: up quarks, down quarks and electrons.
The antineutron, although neutral like the neutron, is distinguishable from the neutron because it is composed of two anti-down quarks and one anti-up quark.
The antineutron contains one anti-up quark and two anti-down quarks, giving it a charge of 0, just like the regular neutron.
These include the charm and top quarks, which are heavy copies of the up quark, and the strange and bottom quarks, which are heavy copies of the down quark.
This is because the proton is made of two up quarks and a down quark, while the neutron comprises two downs and an up.
A neutral pion consists of a down quark and a down antiquark.