Transcript
Particles
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This transcript includes the words sent to the narrator for inclusion in the latest
version of the associated video. Occasionally, the narrator changes a few words
on the fly in order to improve the flow. It is written in a manner that suggests to
the narrator where emphasis and pauses might go, so it is not intended to be
grammatically correct.
The Scene numbers are left in this transcript although they are not necessarily
observable by watching the video.
There will also be occasional passages in blue that are NOT in the video but that
might be useful corollary information.
There may be occasional figures that suggest what might be on the screen at
that time.
ELECTRON
This is how we represent an electron visually. The particle itself is a fundamental
particle and is too small to be seen by any imaginable instrument of observation.
So we instead represent the properties that allow the electron to interact.
The central small dot represents the “weak charge” of the electron. This charge
– entirely separate from electric charge – gives rise to the Weak Nuclear Force.
This force causes radioactive decay and its typical range is much smaller than
the diameter of a proton.
The larger volume of shifting purple is meant to represent the Electric Charge of
the electron. This charge is the generator of the Electromagnetic Force which
has infinite range although the drop off in strength is pretty dramatic as we move
away from the electron.
The Electromagnetic Force is how electrons interact with other electrically
charged particles and with magnetic fields. These interactions make the
structure of atoms and molecules possible. This gives rise to almost all of the
complexity that we see around us.
UP QUARK
This is how we represent the “up quark” visually. The particle itself is a
fundamental particle and is too small to be seen by any imaginable instrument of
observation. So we instead represent the properties that allow the up quark to
interact.
The central small dot represents the “weak charge” of the up quark. This charge
– entirely separate from electric charge – gives rise to the Weak Nuclear Force.
This force causes up quarks and down quarks to swap flavours and its typical
range is much smaller than the diameter of a proton.
Surrounding that is a volume depicted as gold for the up quark. This represents
the electric charge of the up quark, which has a positive charge of +2/3 units The
electric charge is the generator of the Electromagnetic Force which has infinite
range although the drop off in strength is pretty dramatic as we move away from
the quark.
The larger volume of shifting red, green, and blue is meant to represent the color
charge which generates the Strong Nuclear Force. This is the force that holds
quarks together in a proton or neutron. And a residuum of this force holds the
protons and neutrons together in the nucleus of atoms. This force is a hundred
times stronger than the Electromagnetic force, but it’s range is limited to about
the size of a proton.
DOWN QUARK
This is how we represent the “down quark”. The particle itself is a fundamental
particle and is too small to be seen by any imaginable instrument of observation.
So we instead represent the properties that allow the down quark to interact.
The central small dot represents the “weak charge” of the down quark. This
charge – entirely separate from electric charge – gives rise to the Weak Nuclear
Force. This force causes the down quark to change into an up quark, and its
typical range is much smaller than the diameter of a proton.
Surrounding that is a volume depicted as purple for the down quark. This
represents the electric charge of the down quark, which has a negative charge of
-1/3 units The electric charge is the generator of the Electromagnetic Force
which has infinite range although the drop off in strength is pretty dramatic as we
move away from the quark.
The larger volume of shifting red, green, and blue is meant to represent the color
charge which generates the Strong Nuclear Force. This is the force that holds
quarks together in a proton or neutron. And a residuum of this force holds the
protons and neutrons together in the nucleus of atoms. This force is a hundred
times stronger than the Electromagnetic force, but it’s range is limited to about
the size of a proton.
PROTON
This is our depiction of a proton. It is composed of two up quarks and one down
quark (as you can see from the tiny rings of color near the center of each quark.)
The overall charge of the proton is positive and so we have given it a gold shell.
(note that we can simply add the charges of the individual quarks to get the
charge of the proton)
The red, green, and blue colors of the quarks represent the color charge which
generates the Strong Nuclear Force that holds them together. It comes in three
different charges – represented here by the three colors, and for different colors
the force is attractive.
The mediator of the Strong Force (the particle that is exchanged in an
interaction) is a gluon. We represent gluon exchange as the occasional wispy
strings between the quarks. As you can see the gluons have color themselves,
and each gluon exchange causes the quarks involved to swap color.
Although we show the quark motion inside the proton as leisurely, they are
actually traveling close to the speed of light.
Oh, and protons taste sour – like vinegar and lemonade.
NEUTRON
This is our depiction of a neutron. It is composed of two down quarks and one up
quark (as you can see from the tiny rings of color near the center of each quark.)
The overall charge of the neutron is neutral and so we have given it a silver shell.
(note that we can simply add the charges of the individual quarks to get the
charge of the neutron. )
The red, green, and blue colors of the quarks represent the color charge that
generates the Strong Nuclear Force that holds them together. It comes in three
charges – represented here by the three colors, and for different colors the force
is attractive.
The mediator of the Strong Force (the particle that is exchanged in an
interaction) is a gluon. We represent gluon exchange as the occasional wispy
strings between the quarks. As you can see the gluons have color themselves,
and each gluon exchange causes the quarks involved to swap color.
Although we show the quark motion inside the neutron as leisurely, they are
actually traveling close to the speed of light.
NEUTRINO
This is how we represent a neutrino. The particle itself is a fundamental particle
and is too small to be seen by any imaginable instrument of observation. So we
instead represent the property that allows the neutrino to interact.
The white area represents the “weak charge” of the neutrino. This charge –
entirely separate from electric charge – gives rise to the Weak Nuclear Force.
This force allows the neutrino to interact -- but only very weakly and its typical
range is much smaller than the diameter of a proton.
Neutrinos are produced when a down quark decays into an up quark, and an
electron. Conservation laws require that a tiny neutral particle is created in beta
decay and that particle is the neutrino (well -- technically an ANTI-neutrino)
Because the neutrino only interacts through the weak force (and negligible
gravity) it almost never interacts with other particles on its own. Millions of
neutrinos stream through your body every second totally unnoticed and
unnoticeable.
GLUONS
Gluons mediate the Strong Force. They have no mass, no electric charge and
no weak charge. So depicting gluons visually is a real challenge. To begin with,
there are eight of them, and each carries a combination of color charge.
Secondly, there are no free gluons, they exist only virtually when two quarks
interact. Third, since the gluons have their own color charge, they generate
secondary virtual gluons, and these generate other gluons, ad infinitum.
This means there is such an ongoing storm of these gluons that the whole
process is impossibly complicated.
But undaunted, we press on. We know that when gluons cause two quarks to
interact, the quarks swap color, and since color is conserved, the gluon must
have at least two colors of its own.
Next, we know that the strong force mediated by the gluons increases in
strength, as the quarks get farther apart. This means the gluon field is what is
called a “flux tube” and leads to a gluon shaped like a string.
Putting all these ideas together leads to the depiction you see on the screen.
PHOTONS
Photons are the gauge bosons – the force carriers -- for Electromagnetism.
Whenever charged particles interact, photons are exchanged.
They have no mass, no electric charge, no weak charge, and no color charge –
the epitome of almost nothing at all. And yet here is where it’s at! Since they are
responsible for all electron and proton interaction, everything we do in our
everyday life from moving a mouse to running in the park relies on the exchange
of photons.
They are energy, contained in shifting and changing Electric and Magnetic Fields
Like all particles with no rest mass, photons travel at the speed of light. They
cannot come to rest.
Photons in the range of visible light carry just enough energy to excite a single
molecule in a photoreceptor cell of your eye.
INTERMEDIATE VECTOR BOSONS
Weak bosons, also called Intermediate Vector Bosons, are the exchange
particles for the Weak Nuclear Force. There are three of them called W+, W-,
and Z0. They are very massive, each being 80-90 times as heavy as a proton.
Because they are so heavy, the uncertainty principle allows them only an
extremely short range when they act as force carriers. So the Weak Nuclear
Force has a range only about 1/100 the diameter of a proton.
The W bosons cause quarks to change flavor while the Z has an effect in an
esoteric type of interaction called “neutral currents”.
GRAVITONS
Gravitons are the as-yet undiscovered force carriers for Gravity. Because of the
great success of the Standard model in describing the other three forces with
exchange bosons, it is assumed that gravity has a gauge boson as well. It’s
properties have been extrapolated. It is a massless, stable, spin = 2 particle that
travels at the speed of light.
Gravitons may not be constrained to the dimensions of space and time that we
experience