universe.exe

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universe.exe
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Cosmic microwave background
Our Universe is filled with photons from the
time of atom formation (380,000 yrs). They were
produced during the BIG BANG. Their temperature
distribution gives information about the age and
composition of the universe.
Microwave Anisotropy Probe
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Temperature Maps
Earth
Universe
Relic radiation from the big bang fireball began
its journey as visible light 13 billion years
ago. During its long journey the Universe has
expanded and its wavelength has been stretched to
microwave wavelengths of a few cm. Picture above
shows hot and cold fluctuations which seeded
clusters of galaxies. The sound you hear is the
(frequency shifted) sound of the big bang
during the first 700,000 years, based on
BOOMERANG data.
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means the Universe is flat
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The Energy Budget of the Universe
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What have we learned from High Energy Physics?
- Matter is made of particles (particle physics)
To understand this, take an apple and a knife,
and cut the apple in half once. Then cut one half
in half again. Then continue the process. After
some number of cuts you will arrive at a single
atom.
Question how many cuts are required?
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The nucleus of the atom is positively charged
It is made of protons (p) and neutrons (n)
The protons and neutrons are made of charged
quarks
The quarks also carry a new colour charge
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I think I finally understand atoms
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Nothing lasts for ever
The (free) neutron is radioactive and decays
after 15 minutes into proton, electron and
neutrino (electron-like neutral particle)
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Neutrinos from the Sun
Question How many neutrinos from the Sun are
passing through your fingernail in one second?
Answer 40 billion! day and night since
neutrinos can pass right through the Earth
without interacting
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W particles the left-handed alchemists
Just like rifle bullets, quarks and leptons spin
as they whizz along
The quarks and leptons can only see W particles
if they spin to the left!
This shatters mirror symmetry!
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The four forces of Nature
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Quarks and Leptons
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What is the origin of the particle masses?
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The Higgs Boson
In the Standard Model the origin of mass is
addressed using a mechanism named after the
British physicist Peter Higgs.
This predicts a new particle the Higgs
boson.
What is the Higgs boson? In 1993, the
then UK Science Minister, William Waldegrave,
issued a challenge to physicists to answer the
questions 'What is the Higgs boson, and why do we
want to find it?' on one side of a single sheet
of paper. This cartoon is based on David
Millars winning entry.
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The CERN Large Hadron Collider (LHC) will
collide protons on protons at energy of 14
trillion electron Volts (14 TeV)
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The CERN Large Hadron Collider c.2007
Atlas
particle_event_full_ns.mov
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Isnt all this too expenive?
The practical benefits of Particle Physics
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discovery of electrons gave us electronics
- discovery of positron
gave us positron emission tomography -
discovery of the Internet at a particle physics
lab CERN
The intellectual benefits of Particle Physics
- the greatest
adventure of all is the voyage of scientific
discovery - like
building a cathedral over generations
- same reason as Chinese
went into space
- (doing particle physics) will do
nothing to defend our country except to make our
country worth defending Robert Wilson
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Neutrino Oscillations
(only possible if neutrinos have mass)
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Atmospheric oscillations have
been seen
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Solar oscillations have
also been seen
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Neutrino Mass
The discovery of neutrino oscillations and hence
mass is the greatest discovery in particle
physics in the past 20 years (since W and Z)
So neutrino mass implies new physics beyond the
Standard Model!
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A theoretical interpretation
2. Neutrinos mix strongly with one another
These two facts can be explained by introducing
one new heavy neutrino into the Standard Model
which spins to the right (plus some other
less important right-handed neutrinos).
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This is based on the see-saw mechanism
Thanks to David King
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This is based on the see-saw mechanism
Thanks to David King
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What about Super- symmetry?
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Quote from Ed Witten in preface of Gordon Kanes
book Supersymmetry
Supersymmetry, if it holds in nature, is part of
the quantum structure of space and time

Discovery of supersymmetry would be one of the
real milestones in physics

Indeed, supersymmetry is one of
the basic requirements of string theory

Discovery of
supersymmetry would surely give string theory an
enormous boost
The search
for supersymmetry is one of the great dramas in
present day physics.
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What is Supersymmetry ?
There are two types of particles in nature
fermions and bosons.
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What about the Higgs Boson?
A further non-interacting singlet Higgs and
Higgsino can even explain the origin of Higgs
mass itself (Elliott, SFK, White 93-95)
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Desperately seeking SUSY
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What has SUSY ever done for us?
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So what else has SUSY ever done for us?
SUSY provides an excellent candidate for dark
matter the spin ½ partner to the photon which is
the lightest SUSY particle and is cosmologically
stable called the photino!
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But what else has SUSY ever done for us?
SUSY provides the basis for cosmological theories
in which the Universe naturally inflates to its
present size, and explain how the microwave
background radiation appears isotropic
For example a SUSY version of the Standard Model
with extra Higgs singlets has been constructed
that explains inflation, large scale structure,
the origin of Higgs mass, and the origin of
right-handed neutrino mass (Bastero-Gi,SFK, Di
Clemente)
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OK, but what else has SUSY ever done for us?
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string1.avi
Strings live in 11 dimensions
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Why wouldnt we notice extra dimensions?
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Brane New Worlds
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Top-down or bottom-up?
Energy
1 trillion trillion Volts
1 trillion Volts
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The Future of Particle Physics
Neutrino Physics
SUSY
Cosmology
Strings