Don Lincoln Fermilab Fermilab Physics Don Lincoln.
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Transcript of Don Lincoln Fermilab Fermilab Physics Don Lincoln.
Don Lincoln
Fermilab
Fermilab Physics
Don Lincoln
What’s 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).
It’s a lot of fun.
Periodic Table
All atoms are madeof protons, neutronsand electrons
Helium Neon
u
du u
d d
Proton NeutronElectron
Gluons hold quarks togetherPhotons hold atoms together
• 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
So what’s the deal on antimatter?
Fact
or
Fiction?
WierdoTrekkie-geekthing?
Nope!
So what’s the deal on antimatter?
+ =
1 gram ofmatter
1 gram ofantimatter
Energy release equivalent to
Hiroshima explosion
FACT: Fermilab has the largest amount of antimatter anywhere on the planet.
Ummmm…Where’s the exit?
Question:What would happen if you took all of the antimatter ever made at Fermilab and combined it with an equal amount of matter?
Answer:Enough energy to raiseyour 20 oz coffee from room to drinkable temperature
Now (15 billion years)
Stars form(1 billion years)
Atoms form (300,000 years)
Nuclei form (180 seconds)
??? (Before that)
4x10-12 seconds
Nucleons form (10-10 seconds)
Quarks differentiate (10-34 seconds?)
=e2/ħc
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
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.
Fermilab’s Wilson Hall
Saint-Pierre Cathedral in Beauvais, France1272 A.D.
Why the Buffalo?
Nah...that’s why we have graduate students....and they’re cheaper....
Radiation Detector?
Increasing ‘Violence’ of Collision
ExpectedNumber
ofEvents
Run II
Run I
Increased reach for discovery physicsat highest masses
Huge statistics for precision physicsat low mass scales
Formerly rare processesbecome high statisticsprocesses
1
10
100
1000
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
How Do You Detect Collisions?
• Use one of two large multi-purpose particle detectors at Fermilab (DØ and CDF).
• They’re designed to record collisions of protons colliding with antiprotons at nearly the speed of light.
• They’re basically cameras.
• They let us look back in time.
DØ Detector: Run II
30’
30’
50’
• 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).
Remarkable Photos
This collision is the most violentever recorded (and fully understood). It required thatparticles hit within 10-19 m or 1/10,000 the size of a proton
In this collision, a top and anti-top quark were created,helping establish their existence
Highlights from 1992-1996 Run
• Limits set on the maximum size of quarks (it’s gotta be smaller than 1/1000 the size of a proton)
• Supported evidence that Standard Model works rather well (didn’t see anything too weird)
• Studied quark scattering, b quarks, W bosons
• Top quark discovery 1995
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.
• We’ve identified 50 top quark events and expect 50 more which look like top, but aren’t.
Run II
×10
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??
?
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). Fermilab’s Leon Lederman co-authored a book on the subject called The God Particle.
top
bottom
Undiscovered!
Particle gains mass Higgs boson manifests
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? Explainhow the Higgs mechanism works in simple terms.
The winner:David Miller
How do you find a Higgs Boson?
Go to a CD storewww.higgsboson.com
Go to Fermilab
The Challenge:
Higgs is 10 rarer than the top quark was.
We will have 10 times more data to look through.
So it’s a wash….
Except…things that look like a Higgs Boson, but aren’t are much more common.
Bottom line
It’s going to be hard!
Data-Model Comparison
Data-Model Comparison
Run II: What are we going to find?
I don’t know!
Improve top quark mass and measure decay modes.
Do Run I more accurately
Supersymmetry, Higgs, Technicolor, particles smaller than quarks, something unexpected?
What’s up for the rest of today?1. Q & A
2. Then choicea. 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.
b. For those more interested in asking questions, I’ll hang around for a while. The down side is you can then only see the 15th floor.
3. After the tour, there are other scientists, with different fields of expertise on the 15th floor, who can answer other questions.