Every particle has an anti-particle

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MODERN PHYSICS II
Every particle has an anti-particle - Electron
and positron - Proton and antiproton -
Neutrino and antineutrino - Quarks and
anti-quarks - They both have mass -
They have opposite sign - If they meet, they
self-annihilate and release energy
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How much energy is released if a proton meets an
antiproton? How much energy is released if a
positron meets an electron?
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The energy is released as gamma radiation a
gamma ray! Gamma rays are another name for high
intensity electromagnetic radiation (see ref
table). They are transverse waves, propagate
through a vacuum at v c, and interact with
matter better than neutrinos but worse than
electrons, protons, and neutrons.
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Note that charge is unitary (1, 0, -1) outside
the nucleon and fractional (/- 1/3 or /- 2/3)
inside it. Charge is quantized.
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Note that charge is unitary (1, 0, -1) outside
the nucleon and fractional (/- 1/3 or /- 2/3)
inside it. Charge is quantized.
Light (not heavy)
Heavy
These dont live long
Here there be nucleons
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Note that charge is unitary (1, 0, -1) outside
the nucleon and fractional (/- 1/3 or /- 2/3)
inside it. Charge is quantized.
Light (not heavy)
Heavy
These dont live long
Here there be nucleons
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• What is the world made of?"
• and
• "What holds it together?
• All matter is comprised of Leptons and Quarks.
• There are 6 leptons and 6 quarks
• There are 4 fundamental forces Strong, Weak,
  Electromagnetic, Gravity.

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Leptons

• They are elementary particles
• Have no measurable size or structure
• Known leptons
• Electron electron neutrino
• Muon muon neutrino
• Tau tau neutrino
• The neutrinos do not have electric charge
• And each of the six has an anti-particle

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Electron, Muon, Tau

• All three have a charge of -1
• The electron is found in everyday matter
• The muon and the tau have a lot more mass than
  the electron
• The muon and the tau are not part of everyday
  matter because they have very short lifetimes

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Neutrinos

• Neutrinos are three of the six leptons
• They have no electrical or strong charge
• Neutrinos are very stable and are all around
• Most neutrinos never interact with any matter on
  Earth
• Around 60,000,000,000,000 neutrinos pass through
  you every second. (6x1014/sec)

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Quarks

• Elementary particles
• Used to create other particles
• Six quarks
• Up
• Down
• Strange
• Charm
• Bottom
• Top

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Quarks

• Each quark has an anti-particle
• Quarks have a physical property called color, it
  could be blue, green or red
• Each color also has an anti-color
• They are not really different colors, it is a
  property, like charge
• Quarks cannot exist individually because the
  color force increases as they are pulled apart.

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Hadrons

• Consist of particles that interact through the
  strong force.
• Hadrons are set apart from leptons because they
  are composed of other, smaller particles
• Separated into two categories
• Baryons Mesons
• These are distinguished by their internal
  structure
• Most of the mass we observe in a hadron comes
  from its kinetic and potential energy.

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Baryons

• Baryons are composed of three quarks
• All but two baryons are very unstable, they are
• The proton and neutron!!
• Most baryons are excited states of protons and
  neutrons
• Other Baryons

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Protons Neutrons

• Protons are made of three quarks, two up quarks
  and a down quark
• This is written as uud
• Neutrons are also made up of three quarks, one up
  quark and two down quarks
• This is written as udd

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Mesons

• Composed of a quark and anti-quark
• All are very unstable
• They are not part of everyday matter
• Have a mass between that of the electron and the
  proton
• All decay into electrons, positrons, neutrinos
  and photons.

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Generations of Matter

• Mass increases from 1 generation to the next
• Going down in each generation, the charges are
• 2/3, -1/3, 0, -1
• These are all in multiples of the elementary
  charge

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Fundamental Forces
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The Four Fundamental Forces
Strong Weak
Electromagnetic Gravity

• These forces include interactions that are
  attractive or repulsive, and produce decay and
  annihilation.

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The Strong Force

• The strongest of the 4 forces
• Is only effective at distances less than 10-15
  meters (about the size of the nucleus)
• Holds quarks together
• This force is carried by gluons

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Residual Strong Force

• We know that protons and neutrons are bound
  together in the nucleus of an atom
• This is due to the residual strong force that is
  binding the quarks together in each of the baryons

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The Weak Force

• A very short-ranged nuclear interaction that is
  involved in beta decay
• This is ten thousand billion times weaker than
  the strong force (10-13)
• Effective only at distances 1000 times smaller
  than the strong force
• This force is carried by the W, W-, and the Zo
  particles.

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The Electromagnetic Force

• Causes opposite charges to attract and like
  charges to repel
• Carried by a particle called a photon
• Its effects decrease with the inverse square of
  the separation (as we learned earlier)

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Photons

• Carry the electromagnetic force
• They have no mass
• Photons do not carry charge
• Photons do carry energy

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Gravity

• Has a negligible effect on elementary particles
• A long-range force (as we learned earlier)
• Carried by the graviton
• This is by far the weakest of the 4 fundamental
  forces

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Gravitons

• Have not yet been observed
• Although, there is indirect evidence that
  gravitons do exist
• Gravitons should have no mass or charge
• If gravitational energy is radiated, it would be
  in discrete quanta

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Fundamental Forces Summary
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Which Fundamental Interaction/Force is
responsible for

• Friction?
• Electromagnetic.
• Nuclear Bonding?
• Residual Strong Nuclear.
• Orbiting Planets?
• Gravity.
• Which force carriers have not been observed?
• Gravitons (Gluons have been observed indirectly)

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More About Quarks
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More About Leptons
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Just Kidding

• Other name candidates included the
• "hold-on,"
• "duct-tape-it-on,"
• "tie-it-on!"

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The Muon and Tau

• These two heavier leptons decay into lighter
  leptons or quarks
• When they decay, three particles are produced
• One of the particles produced is always its
  corresponding neutrino
• The other particles could be a quark and its
  anti-quark or another lepton and its
  anti-neutrino
• Muon decay experiment on Mt. Washington in NH was
  explained through Einsteins theory of
  relativity.

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Electrons dont stay in pretty orbits, either.
We like to think of electrons as particles, but
they also act like waves and spend part of the
time inside the nucleus!
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All of the known energy in the universe comes
from the conversion of mass into energy - In
stars, - Fusion turns hydrogen into Helium
(with several stops along the way) - Fusion
turns Helium into Carbon and Nitrogen and Oxygen
and Iron - When stars run out of Helium
they blow up - Spewing all the bits into
space!
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Covered Standards Mon 5/7 5.3f Among other
things, mass-energy and charge are conserved at
all levels (from subnuclear to cosmic). 5.3g
The Standard Model of Particle Physics has
evolved from previous attempts to explain the
nature of the atom and states that atomic
particles are composed of subnuclear particles
the nucleus is a comglomeration of quarks which
manifest themselves as protons and neutrons
each elementary particle has a corresponding
antiparticle Stress Tues 5/8 5.3b Charge is
quantized on two levels. On the atomic level,
charge is restricted to multiples of the
elementary charge (charge on the electron or
proton). On the subnuclear level, charge appears
as fractional values of the elementary charge
(quarks). 5.3j The fundamental source of all
energy in the universe is the conversion of mass
into energy.
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NYS Regents Standards
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5.3b Charge is quantized on two levels. On the
atomic level, charge is restricted to multiples
of the elementary charge (charge on the electron
or proton). On the subnuclear level, charge
appears as fractional values of the elementary
charge (quarks). 5.3f Among other things,
mass-energy and charge are conserved at all
levels (from subnuclear to cosmic). 5.3j The
fundamental source of all energy in the universe
is the conversion of mass into energy. 5.3g The
Standard Model of Particle Physics has evolved
from previous attempts to explain the nature of
the atom and states that atomic particles are
composed of subnuclear particles the nucleus is
a comglomeration of quarks which manifest
themselves as protons and neutrons each
elementary particle has a corresponding
antiparticle
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observe and explain energy conversions in
real-world situations recognize and describe
conversions among different forms of energy in
real or hypothetical devices such as a motor, a
generator, a photocell, a battery 4.1b Energy may
be converted among mechanical, electromagnetic,
nuclear, and thermal forms.
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4.3a An oscillating system produces waves. The
nature of the system determines the type of wave
produced. 4.3b Waves carry energy and
information without transferring mass. This
energy may be carried by pulses or periodic
waves. 4.3d Mechanical waves require a material
medium through which to travel. 4.3g
Electromagnetic radiation exhibits wave
characteristics. Electromagnetic waves can
propagate through a vacuum. 4.3j The absolute
index of refraction is inversely proportional to
the speed of a wave. 4.3k All frequencies of
electromagnetic radiation travel at the same
speed in a vacuum. 4.3l Diffraction occurs when
waves pass by obstacles or through openings. The
wavelength of the incident wave and the size of
the obstacle or opening affect how the wave
spreads out. 4.3 Explain variations in wavelength
and frequency in terms of the source of the
vibrations that produce them, e.g., molecules,
electrons, and nuclear particles. iv.
differentiate between transverse and longitudinal
waves
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5.3a States of matter and energy are restricted
to discrete values (quantized). 5.3c On the
atomic level, energy is emitted or absorbed in
discrete packets called photons. 5.3 Compare
energy relationships within an atoms nucleus to
those outside the nucleus. i. interpret
energy-level diagrams ii. correlate spectral
lines with an energy-level diagram
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5.3h Behaviors and characteristics of matter,
from the microscopic to the cosmic levels, are
manifestations of its atomic structure. The
macroscopic characteristics of matter, such as
electrical and optical properties, are the result
of microscopic interactions. 5.3i The total of
the fundamental interactions is responsible for
the appearance and behavior of the objects in the
universe.
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5.3d The energy of a photon is proportional to
its frequency. 5.3e On the atomic level, energy
and matter exhibit the characteristics of both
waves and particles.