Components of the Standard Model of
Fundamental Particles and Interactions
Click HERE to view particle chart in its entirety!
(Indeed, an improved view.)
The "Standard Model" is a term used to describe the quantum theory
that includes the theory of strong interactions
(quantum chromodynamics or QCD) and the unified theory of
weak and electromagnetic interactions (electroweak).
Gravity is included on this chart because it is one of the
fundamental interactions even though not part of the "Standard Model"
Larger
(115k, gif)
Larger
(72k, jpg)
The text of the figure reads:
If the protons and neutrons in this picture were 10 cm across, then the
quarks and electrons would be less than 0.1 mm in size and the
entire atom would be about 10 km across.
Spin is the intrinsic
angular momentum of particles. Spin is given in units of h-bar,
which is the quantum unit of angular momentum, where
hbar=h/2pi = 6.58*10^-25 GeV s = 1.05*10^-34 J s.
Electric charges are given in units of the
proton's charge.
In SI units the electric charge of the proton is 1.60 * 10^-19 coulombs.
The energy unit of
particle physics is the electron volt (eV),
the energy gained by one electron in
crossing a potential difference of one volt.
Masses are given in GeV/c2.
(Remember E = mc2
), where 1 GeV = 10^9 eV = 1.60 * 10^-10 joule.
The mass of the proton is 0.938 GeV/c^2 = 1.67*10^-27 kg
Larger(78k, gif)
Larger
(87k, jpg)
Top quark discovered
(Fermilab news release)
Larger
(66k, gif)
Larger
(55k, jpg)
Color Charge
Each quark carries one of the three types of "strong charge",
also called "color charge".
These charges have nothing to do with the colors of visible light.
There are eight possible types of color charge for gluons.
Just as electrically charged particles interact by exchanging photons,
in strong interactions color-charged particles exchange gluons.
Leptons, photons, and W and Z bosons
have no color charge and hence no strong interaction.
One cannot isolate quarks and gluons;
they are confined into color-neutral hadrons.
This confinement (binding) results from
multiple exchanges of gluons among the color-charged objects.
Confinement
As color-charged particles (quarks and gluons ) are separated,
the color force between them approaches a constant
value and the energy in the color-force field increases.
The energy eventually is converted into additional
quark-antiquark pairs.
The objects that finally emerge are color-neutral combinations called
hadrons (mesons and baryons).
Larger
(29k, gif)
Larger
(27k, jpg)
Larger
(32k, gif)
Larger
(25k, jpg)
Residual Strong Interactions
The strong binding of the color-neutral protons and neutrons to
form nuclei is due to residual strong interactions
between their color-charged constituents.
It is similar to the residual electrical interaction
which binds electrically neutral atoms to form molecules.
It can be viewed as the exchange of mesons between the hadrons.
Properties of the Interactions
Larger
(52k, gif)
Larger
(39k, jpg)
Matter and Antimatter
For every particle type there is a corresponding antiparticle type,
denoted by a bar over the particle symbol. Particle and antiparticle
have identical mass and spin but opposite charges. Some
electrically neutral bosons
(e.g, Z0,
gamma, and eta_c = c cbar but not
K0 = ds) are their own antiparticles.
These diagrams are an artist's conception of physical processes.
They are not exact and have no meaningful scale.
Green shaded areas represent the cloud of gluons or the gluon field,
red lines the quark paths, and black lines the paths of leptons.
Charts
Larger
(26k, gif)
Larger
(19k, jpg)
The text of the figure reads:
A neutron decays to a proton,
an electron, and an antineutrino via a virtual (mediating) W
boson. This is neutron beta decay.
Larger
(29k, gif)
Larger
(22k, jpg)
The text of the figure reads:
An electron and positron (antielectron)
colliding at high energy can annihilate to
produce
D+ and D-
mesons via a virtual Z boson or a virtual photon.
Larger
(33k, gif)
Larger
(22k, jpg)
The text of the figure reads:
The c and cbar quarks in an eta_c meson annihilate into virtual gluons.
Quark pair production in the gluon cloud sometimes gives a
pi+,
K0,
and K-
as the final products.
CPEP is a non-profit organization of teaches, physicists, and
educators. For information on the chart, software, book, packet of
hands-on classroom activities, and workshops, look on the
WWW (URL /pdg.lbl.gov/cpep.html),
send e-mail to
pdg@lbl.gov.
or write:
CPEP, MS 50-308, Lawrence Berkeley
National Laboratory, Berkeley, CA 94720, USA.
Corporate and private donations, as well as national laboratory funding,
have been and remain crucial to the success of this project.
-
Exclusive Worldwide Distribution by:
- Science Kita & Boreal Laboratories
The chart is copyrighted in 1995 by CPEP.
We thank Peter Berglund
peter@neuro.hut.fi
for taking the time to scan the various components of the Chart, key in
the text, and design this layout.
Copyrights and disclaimers
and
other funding
Betty Armstrong
21-AUG-1995
