2. Quarks, Leptons, Baryons, oh my!
The universe is filled with a vast assortment
of different particles. These particles make
everything look, work, and act the way they
do in our world.
On the right there is a picture of some of the
most well known particles. These particles
include the proton, the neutron, and the
electron. These particles make up atoms,
which are the building blocks of normal
matter, but all of these particles, excluding the
electron are made up of even smaller
particles called quarks.
All of these different particles are divided into different classes like the baryons, mesons, and
leptons. Baryons consist of some of the larger particles like the proton and the neutron.
Mesons are made up of very interesting particles like the pion and some mesons are even
heavier than a proton. Lastly, the Leptons are fundamental particles like the electron.
3. The different quarks
Quarks are the particles that make up most of the particles in the atom. Only the
fundamental electron is not made up of these little building blocks. They are a fundamental
particle, which means that they are not a composite particle, or made up of smaller entities.
They are strongly interacting and never appear singly. They are the building blocks of the
baryons and meson particles and in the picture above you can see that they have a picture of
the inside of a proton and it has three different colored balls inside. Each of these balls is a
quark, the reason that they are multicolored is because quarks come in three colors which is
called a color charge. The quarks can either be colored red, green, and blue. Antiquarks, the anti
particle to the quark, come in the colors of antired, antigreen, and antiblue. If a red, a green,
and a blue quark are combined they become colorless. The same goes for their anti particle
pairs. A proton or any baryon has a total of three quarks inside of it. Quarks are held in protons
and other particles by gluons which are interacting particles whose pulling force is increased the
farther the quark is from the center of the particle. This makes it nye on impossible to isolate a
single quark. To date we have never actually seen a quark by itself.
4. Baryons
Baryons are some of the most massive particles
in the particle zoo. On the right you can see two
of the most well known particles, which also
happen to be baryons. They are the proton and
neutron. Each baryon has three quarks in it and
each quark has something called baryonic
charge. Every quark has a baryonic charge of
1/3, making a proton which has three quarks
have a baryonic charge of one. Baryons are also
part of a group called the Hadrons which are
composite particles made up of quarks. The
mesons also share the distinction of being in this
group.
5. Mesons
Mesons are very interesting particles. They
are classified in the same group as baryons
(the Hadrons group) which means that
mesons are also made out of quarks. But
unlike baryons, mesons are made up of
one regular quark and one anti-quark
making mesons their own anti-particle.
Talk about not liking your relatives.
Some mesons are very massive, even more
massive than the proton. Mesons are not all
very massive as there is the pion, which is
the least massive meson. Mesons are also
very unstable, lasting no longer than a few
hundredths of a microsecond.
6. Leptons
Leptons are fundamental particles and contain no quarks. Leptons include six
different particles which are the tau, the muon, the electron, tau-neutrino,
muon-neutrino, and the electron-neutrino. The electron is most likely the most
well known lepton. It is found whizzing around the nucleus or the center of
atoms. The second most well known lepton is the neutrino which is a very weak
interacting particle. Neutrinos are created as a byproduct of the nuclear fusion
inside of stars and right now there is about 65 billion solar neutrinos passing
through every square centimeter perpendicular to the direction of the sun every
second.
7. Bosons Fermions
Bosons are social particles, that
Fermions are anti-social particles,
include the pion, which is a meson.
that include quarks, leptons, and
In fact all mesons are bosons, the
baryons. These are all fermions,
reason behind this is that all particles
because they all have an odd
that have an even number of quarks
number of quarks. Fermions are
are boson. Bosons are very social
“anti-social” because they follow
particles which means that two
the exclusion principal, which says
identical bosons can occupy the
that no two identical fermions can
same state of motion at the same
occupy the same state of motion
time and “prefer” to.
at the same time.
8. The Higgs Boson
The Higgs Boson is a theoretical particle
that creates the Higgs field, which gives
particles their mass. The Higgs boson
may have been detected at the Large
Hadron Collider this year. The Higgs is
very unstable, decaying into other
particles almost immediately. It has no
spin, electric charge, or color charge and
is classified as a boson.
Quarks
Gluons
9. Sources:
Ford, W. Kenneth. The Quantum
World, Quantum Physics for
Everyone. Cambridge MA: Harvard
University Press, 2004.
http://en.wikipedia.org/wiki/Higgs_b
oson. Higgs Boson-Wikipedia. Access
date, 12/4/12.
