Don Lincoln

1
Fermilab Physics Don Lincoln

• Don Lincoln
• Fermilab

2
Whats the Point?

• High Energy Particle Physics is a study of the
  smallest pieces of matter.
• 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).
• Its a lot of fun.

3
Periodic Table

• All atoms are made
• of protons, neutrons
• and electrons

4

• All particles have anti-particles, which have
  similar properties, but opposite electrical
  charge
• Particles
• u,c,t 2/3
• d,s,b -1/3
• e,?,? -1
• Anti-particles
• u,c,t -2/3
• d,s,b 1/3
• e,?,? 1

Anti-Matter
5
So whats the deal on antimatter?
Fact or Fiction?
Nope!
6
So whats the deal on antimatter?


1 gram of antimatter
1 gram of matter
7
FACT Fermilab has the largest amount of
antimatter anywhere on the planet.
Question What would happen if you took all of
the antimatter ever made at Fermilab and combined
it with an equal amount of matter?
UmmmmWheres the exit?
8
(No Transcript)
9

• Now
• (15 billion years)

Stars form (1 billion years)
Atoms form (300,000 years)
Nuclei form (180 seconds)
Nucleons form (10-10 seconds)
Quarks differentiate (10-34 seconds?)
??? (Before that)
10
ae2/hc
11
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
12
Fermilab Facts

• Named after Enrico Fermi, the famous Italian
  physicist who worked on the Manhattan Project.
• Current Director Michael S. Witherell
• Fermilab encompasses 6800 acres, much of it used
  for prairie restoration and preserving open space
  in the western suburbs.
• Employees about 2000 people.
• Original cost 250,000,000. Approximately the
  same amount in upgrades over the last 30 years.
• Electric bill between 10,000,000 and 20,000,000
• NO classified work is done here, ask all the
  questions and take all the pictures you want.

13
Fermilabs Wilson Hall
Saint-Pierre Cathedral in Beauvais, France1272
A.D.
14
Why the Buffalo?
Nah...thats why we have graduate students....and
theyre cheaper....
15
(No Transcript)
16

• ? 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
100
Increased reach for discovery physics at highest
masses
10
Run II
1
Run I
Increasing Violence of Collision
17
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.

18
DØ Detector Run II

• Weighs 5000 tons
• Can inspect 3,000,000 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).

30
30
50
19
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
20
Highlights from 1992-1996 Run

• Limits set on the maximum size of quarks (its
  gotta be smaller than 1/1000 the size of a
  proton)
• Supported evidence that Standard Model works
  rather well (didnt see anything too
  weird)
• Studied quark scattering, b quarks,
  W bosons
• Top quark discovery 1995

21
The Needle in the Haystack Run I

• There are 2,000,000,000,000,000
  possible collisions per second.
• There are 300,000 actual
  collisions per second, each of them scanned.
• We write 4 per second to tape.
• For each top quark making collision, there are
  10,000,000,000 other types of collisions.
• Even though we are very picky about the
  collisions we record, we have 65,000,000 on tape.
• Only 500 are top quark events.
• Weve identified 50 top quark events and expect
  50 more which look like top, but arent.

Run II 10
22
Top Quark Run I The Summary

• The top quark was discovered in 1995
• Mass known to 3 (the most accurately known quark
  mass)
• The mass of one top quark is 175 times as heavy
  as a proton (which contains three quarks)

Why???
23
In 1964, Peter Higgs postulated a physics
mechanism which gives all particles their
mass. This mechanism is a field which permeates
the universe. If this postulate is correct,
then one of the signatures is a particle
(called the Higgs Particle). Fermilabs Leon
Lederman co-authored a book on the subject
called The God Particle.
Undiscovered!
24
In 1993, William Waldegrave, the British Science
Minister, Announced a contest, the prize for
which was none other than a bottle of very good
champagne.
The contest? Explain how the Higgs mechanism
works in simple terms. The winner David Miller
25
How do you find a Higgs Boson?
The Challenge Higgs is ?10 rarer than the top
quark was. We will have ?10 times more data to
look through. So its a wash. Exceptthings
that look like a Higgs Boson, but arent are much
more common. Bottom line Its going to be hard!
26
Data-Model Comparison
27
Data-Model Comparison
28
Run II What are we going to find?

• I dont know!

Improve top quark mass and measure decay
modes. Do Run I more accurately
Supersymmetry, Higgs, Technicolor, particles
smaller than quarks, something unexpected?
29
Whats up for the rest of today?

• Q A
• Then choice
• For those more interested in the tour, the
  docents will take you to the 15th floor, plus
  tour some of the accelerators and control room.
• For those more interested in asking questions,
  Ill hang around for a while. The down side is
  you can then only see the 15th floor.
• After the tour, there are other scientists, with
  different fields of expertise on the 15th floor,
  who can answer other questions.