Hadrons
The reason that fractional electric charges like those of quarks have not
been seen is that the quarks are never found separately, but only in
composite particles called hadrons.
There are two classes of hadrons:
- Baryons:
- Baryons contain three quarks (qqq). For example, protons are 2
up quarks and 1 down quark (uud) and neutrons are 1 up and 2
down quarks (udd).
- Mesons:
- Mesons contain one quark (
)
and an antiquark
(
).
For example, a negative pion
(
)
is
(
)
A pronunciation guide to the particles
Hadron Masses
Why is the world around us made of only the least massive particle types?
