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 made of protons, neutrons and electrons HeliumNeon u d u u d d Proton Neutron Electron Gluons hold quarks together Photons 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? Wierdo Trekkie-geek thing? Nope!

So what’s the deal on antimatter? + = 1 gram of matter 1 gram of antimatter 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 raise your 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) 4x seconds Nucleons form ( seconds) Quarks differentiate ( seconds?)

 =e 2 /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, France 1272 A.D.

Why the Buffalo? Nah...that’s why we have graduate students....and they’re cheaper.... Radiation Detector?

Increasing ‘Violence’ of Collision Expected Number of Events Run II Run I Increased reach for discovery physics at highest masses Huge statistics for precision physics at low mass scales Formerly rare processes become high statistics processes  The Main Injector upgrade was completed in  The new accelerator increases the number of possible collisions per second by  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’ 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 (1,000,000,000,000,000) bytes in the next run (1 PetaByte).

Remarkable Photos This collision is the most violent ever recorded (and fully understood). It required that particles hit within 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 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 massHiggs 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? Explain how the Higgs mechanism works in simple terms. The winner: David Miller

How do you find a Higgs Boson? Go to a CD store 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

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 choice a.For those more interested in the tour, the docents will take you to the 15 th 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 15 th floor. 3.After the tour, there are other scientists, with different fields of expertise on the 15 th floor, who can answer other questions.