Why Study Nature

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Why Study Nature?
Power (Control over it) When will
the Nile flood? (time/astronomy) What will
make my sick baby better? (medicine) How
can I make my spear fly faster and farther?
(physics)
Celebrity Status A-List parties Red carpet
treatment MTV interviews
Because we must. Mankind has always been driven
to understand the world. The world is
inherently simple and beautiful. It can be
understood.
And always Babesnever forget the babes
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As a single, unified thing there exists in us
both life and death, waking and sleeping, youth
and old age, because the former things having
changed are now the latter, and when those latter
things change, they become the former. -
Heraclitus (quoted in
pseudo-Plutarch,
Consolation to
Apollo )
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Being is ungenerated and indestructible, whole,
of one kind and unwavering, and complete. Nor
was it, nor will it be, since now it is, all
together, one, continuous...That it came from
what is not I shall not allow you to say or
think for it is not
sayable
or thinkable that it is not...How might what is
then perish? How might it come into being? For if
it came into being it is not, nor is it if it is
ever going to be. Thus generation is quenched
and perishing unheard of.
- Parmenides circa 480 BC
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Science Is About Simplification
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PHILOSOPHIÆ NATURALIS PRINCIPIA MATHEMATICA
AUCTORE ISAACO NEWTONO Editio tertia MDCCXXVI
Axiomata sive Leges Motus Lex I Corpus omne
perseverare in statu suo quiscendi vel movendi
uniformiter in directum, nisi quatenus a viribus
impressis cogitur statum illum mutare. Lex II
Mutationem motus proportionalem esse vi motrici
impress", et fieri secundum lineam rectam qua
vis illa imprimitur. Lex III Actioni contrariam
semper et æqualem esse reactionem sive corporum
duorum actiones in se mutuo semper esse æquales
et in partes contrarias dirigi.
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PHILOSOPHIÆ NATURALIS PRINCIPIA MATHEMATICA
Author Isaac Newton Third edition (1726) Three
Laws of Motion Law I Every object in a state of
uniform motion tends to remain in that state of
motion unless an external force is applied to
it. Law II The relationship between an object's
mass m, its acceleration a, and the applied force
F is F ma.
Law III For every action there is an equal and
opposite reaction.
Everything pertaining from astronomical motion
to falling here on Earth can be fully described
by Newtons Law of Gravity plus his laws of
motion.
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Science Is About Simplification
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James Clerk Maxwell (1864)
Modern Nomenclature
Three Become one
Electricity
ElectroMagnetism
Magnetism
Light
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• Then may we not fairly plead in reply that our
  true lover of knowledge naturally strives for
  truth, and is not content with common opinion,
  but soars with undimmed and unwearied passion
  till he grasps the essential nature of things ?
• Plato
• Republic

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• Science addresses many things
• What is the ultimate nature of reality?
• What is the simplest expression of nature?
• Amongst all of the undeniable change, is there
  anything that is permanent and enduring?
• How did the universe come into existence and what
  is its ultimate fate?
• What is the ultimate answer to the ultimate
  question?

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What is the root of it all? From where comes
meaning?
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Beauty in the Universe
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Innermost Space

• High Energy Particle Physics is a study of the
  smallest pieces of matter.
• It investigates the deepest and most fundamental
  aspects of nature.
• It investigates (among other things) the nature
  of the universe immediately after the Big Bang.
• It also explores physics at temperatures not
  common for the past 15 billion years (or so).

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Periodic Table
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t
u
d
b
While quarks have similar electric charge, they
have vastly different masses (but zero size!)
c
s
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ae2/hc
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Fermi National Accelerator Laboratory(a.k.a.
Fermilab)

• Begun in 1968
• First beam 1972 (200, then 400 GeV)
• Upgrade 1983 (900 GeV)
• Upgrade 2001 (980 GeV)

Jargon alert 1 Giga Electron Volt (GeV) is
100,000 times more energy than the particle beam
in your TV. If you made a beam the hard way, it
would take 1,000,000,000 batteries
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• ? The Main Injector upgrade was completed in
  1999.
• ? The new accelerator increases the number of
• possible collisions per
  second by 10-20.
• ? DØ and CDF have undertaken massive
• upgrades
  to utilize the increased
• 
  collision rate.
• ? Run II began March 2001

Expected Number of Events
Huge statistics for precision physics at low
mass scales
1000
Formerly rare processes become high
statistics processes
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Increased reach for discovery physics at highest
masses
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Run II
1
Run I
Increasing Violence of Collision
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How Do You Detect Collisions?

• Use one of two large multi-purpose particle
  detectors at Fermilab (DØ and CDF).
• Theyre designed to record collisions of protons
  colliding with antiprotons at nearly the speed of
  light.
• Theyre basically cameras.
• They let us look back in
  time.

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Typical Detector (Now)

• Weighs 5,000 tons
• Can inspect 10,000,000 collisions/second
• Will record 50 collisions/second
• Records approximately 10,000,000 bytes/second
• Will record 1015 (1,000,000,000,000,000) bytes
  in the next run (1 PetaByte).

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30
50
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Spooky?
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Remarkable Photos
In this collision, a top and anti-top quark were
created, helping establish their existence
This collision is the most violent ever recorded
(and fully understood). It required
that particles hit within 10-19 m or 1/10,000
the size of a proton
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Modern Cosmology

• Approximately 15 billion years ago, all of the
  matter in the universe was concentrated at a
  single point
• A cataclysmic explosion (of biblical proportions
  perhaps?) called the Big Bang caused the matter
  to fly apart.

• In the intervening years, the universe has been
  expanding, cooling as it goes.

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Big Bang Theory
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Black Body Radiator

• A black body radiator is one which absorbs all
  light which is incident on it.
• Such a body can also emit light, if sufficiently
  hot.
• Since the universe is the remnant of a hot
  explosion, it should thus have a temperature and
  an afterglow.

Universe
?
?
?
?
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Afterglow From the Big Bang
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Afterglow From the Big Bang

• In 1964, while working at Bell Labs, Penzias and
  Wilson discovered a radio hiss that they couldnt
  make go away.
• They had (by accident!) discovered the remnant
  echo of the Big Bang
• The universe was shown to have a temperature of
  2.726K (-450 F)

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How Does the Afterglow Work?

?

?
?
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?

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?
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Proton Electron Photon

?
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How Does the Afterglow Work?
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Proton Electron Photon

?



?
H
Proton Electron Hydrogen
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Mysteries of the Afterglow
The temperature of the universe is uniform
everywhere to parts per million. Why? The
temperature of the universe has slight
non-uniformities, at the parts per
million. Why? Answers to both of these
questions
exist but are beyond the scope of

this talk. Get Peter to bring in
a
cosmologist soon.
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History of the Universe (Readers Digest Version)
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• Now
• (13.7 billion years)

Stars form (1 billion years)
Atoms form (380,000 years)
Nuclei form (180 seconds)
Nucleons form (10-10 seconds)
Quarks differentiate (10-34 seconds?)
??? (Before that)
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The Universes Recipe
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Mysteries
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The Early Universe

• The forces have been unified. What about the
  particles?

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Standard Model Summary
The Standard Model (quarks, leptons, three
generations and four currently-distinct forces)
Can explain all known experimental data,
from The birth of the universe (10-12 seconds)
to now. Motionless objects, to those traveling at
the speed of light. Temperatures from absolute
zero to the Big Bang. Lotsa stuff.. Cannot
explain The very early universe (before 10-12
seconds). Do the forces unify? Are there many
particles or just strings? Lotsa stuff..
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Data-Model Comparison
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Data-Model Comparison
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• It is not possible to be ignorant of the end of
  things if we know their beginning.
• Thomas Aquinas
• Summa Theologica

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