Top Quark a particle odyssey Todd Huffman University of Oxford * 07/16/96 Top Quark a particle odyssey Outline Introduction The Making of Top (X-section) The Un-making of Top (decay) Detecting Top I decided to call this talk 2001 a particle odyssey because with the millennium approaching I wanted to discuss physics opportunities at the Tevatron in 2001 To give you a brief outline for this talk, first I will start with an introduction into particles physics and then I will discuss the current status of the main high energy Colliders used in particle physics, with particle emphasis to the recent upgrades at the Tevatron. Next I will discuss the physics potential at the Tevatron I will then mention the recent UK involvement and finally give a brief summary Todd Huffman University of Oxford 2/22/2019 *

The Strong, The Weak, and The Light * The Strong, The Weak, and The Light 07/16/96 6 quarks 4 bosons 6 leptons For those of you who aren’t particle physicist and are unfamiliar with what we do. Particle physicist study the elementary particles and forces of nature, and this is the Standard Model, a Periodic Table of what we consider TODAY to be the fundamental particles of nature. Our task is to measure the properties and parameters of this model and to search for new physics not explained by the Standard Model. Currently the Standard Model contains 6 quarks, 6 leptons and 4 bosons (which are carriers of the electromagnetic, strong and weak forces). There are 3 families of quarks and leptons, where each family contains 2 quarks and 2 letpons. The first family listed consists of a up, and down quark, the electron and its neutrino, and with just these four particles we can described all the matter we encounter in everyday life. However, in addition to this there are two additional families and they are exact duplicates of the first family, except for one parameter their mass, which is heavier. 3 generations 2/22/2019 *

Many Tried to find T-quarks All met with Failure up to 1994 2/22/2019

‘Onion’ Model - HEP Detectors Magnet Vertex Calorimeters Tracking Chamber Muon Chambers 2/22/2019

Silicon Vertex Detector Silicon Detectors Reversed biased diodes Crank the reverse voltage up until they are fully depleted Charged Particle liberates electron-hole pairs Small pulse of current Amplify it and record the hit. p n Depletion Region 2/22/2019

Silicon Vertex Detectors ~20 cm 2/22/2019

Drift Chambers for Tracking 2/22/2019

Drift Chambers for Tracking 2/22/2019

Sampling Calorimeters Scintillating plastic Hadron Cal. Steel (CDF) or Uranium 2/22/2019 Charged or Neutral Hadron

Sampling Calorimeters 2/22/2019

Top Decay - Very Simple W+ b t q q t b W- 2/22/2019

CDF-II Detector 2/22/2019

Mass Reconstruction  Houston; we have a problem J2 J1 J3 e+ Which jet goes with t or tbar? Which jets are from b quarks? J4  2/22/2019

Detected Top Candidate Silicon Detector Results 2/22/2019

* 07/16/96 Backgrouds to Top P-Pbar can produce a W along with 4 or 5 jets directly. This background is the most serious to the lepton+jets top decay channels. W+l  u d So What can you do with these detectors at this accelerator? Probably the most well known physics coming out of the Tevatron are the top quark studies. Currently the only place in the world to produce and study the top quark is the Tevatron. However, in run two, instead of hundreds there will be thousands of ttbar events. This will allow precision measurements to be performed for the top mass, and production cross sections, as well as measurements of branching ratios, rare decays and couplings. 2/22/2019 *

Total Events Found Luminosity ~5x1030 cm-2s-1 after 1.5 years Top  two Leptons CDF - 13 events D0 - 7 events Top  single Lepton CDF - 98 events D0 - 31 events How Many of these are Top quarks? Are any of them Top quarks? 2/22/2019

Physics at the Tevatron 2001 * 07/16/96 Physics at the Tevatron 2001 Top Physics Expect over 10,000 tt events in this Run Mass Measured to 3 GeV/c2 s(tt) known to 9% Rare Decays, Couplings, … So What can you do with these detectors at this accelerator? Probably the most well known physics coming out of the Tevatron are the top quark studies. Currently the only place in the world to produce and study the top quark is the Tevatron. However, in run two, instead of hundreds there will be thousands of ttbar events. This will allow precision measurements to be performed for the top mass, and production cross sections, as well as measurements of branching ratios, rare decays and couplings. 2/22/2019 *

Next Lecture - Top useful in Searches for New Physics tbar Non-Standard Model Higgs! 2/22/2019