In the beta decay, an excited down quark
in the neutron degenerates into a ground state down quark
and an excited up and antiup quark pair, [d.
In this process, a down quark
in the neutron changes into an up quark by emitting [W.
The down quarks
somehow carried most of the energy yet rotated in a direction opposite to that of the neutron as a whole.
The new results promise to yield important information about the up and down quarks
that comprise protons and neutrons.
At the simplest level, a proton consists of three quarks: two up quarks, each with an electric charge of +2/3, and a down quark
, with an electric charge of -1/3.
A proton, for example, is made up of two up quarks and one down quark
, and a neutron is made up of two down quarks
and one up quark.
Charm quarks, 100 times heavier than the up and down quarks
that form normal matter, are significantly decelerated by their passage through quark-gluon plasma, offering scientists a unique tool to probe its properties.
The Standard Model, as it is known, says that neutrons and protons are made from still smaller particles called up and down quarks
The quark matter would consist not only of the up and down quarks
that make up protons and neutrons, but also strange quarks, which aren't found in ordinary matter.
19] C) and two Down quarks
(each with the charge of -1/3 x 1.
Ordinary matter, such as protons and neutrons, contains only up quarks and down quarks
, whereas the sigma-bs each contain a bottom quark and either a pair of up quarks or a pair of down quarks
The quarks that behaved as expected were down quarks
, and the one that didn't was an up quark.
Ups and downs Landmark particle-accelerator experiments provided physicists with long-sought data needed to better understand up and down quarks
, the building blocks of ordinary matter (163: 227 *).
There are two common types of quarks known as the up and down quarks
A resulting quark star, for example, would consist of up and down quarks
, which make up protons and neutrons, and also strange quarks, which are heavier and not found in ordinary matter.