D Ø QCD: Past, Present, and Future

1. LM A1U A2U VC Pbar P E P1D P2D f h DØ QCD: Past, Present, and Future Andrew Brandt, University of Texas at Arlington Physics Seminar May 7, 2004 Jefferson Lab

2. Tevatron at Fermilab Chicago CDF Batavia, Illinois DØ DØ DØ CDF p p Run I ( 1992 - 1997 ) : s =1.8 TeV Run II ( 2001 - ? ) : s =1.96 TeV Booster p Tevatron p p source Main Injector & Recycler

3. Upgraded Run II DØ Detector SMT SMT SMT • New Silicon and Fiber Trackers in 2 T magnetic field • New forward muon system with |h|<2 and good shielding • New trigger electronics to deal with 396 ns bunch spacing

4. QCD • Strong Nuclear Force:Quantum ChromodynamicsGluon Exchange, also holds the nucleus together.All quarks carry a color chargeGluons carry two color charges • Different from other Forces:Gluons can interact with other gluons. Quarks and gluons are free at small distances (asymptotic freedom), but not at large distances (confinement)  cannot observe bare color Always observe quarks in multiplets: Baryons qqq (Proton neutron) and Mesons (quark antiquark pair ) Proton: uudAlso contains gluons and quark-antiquark pairs in a sea. Neutron:udd Pion: ud

6. Described by QCD. Parton-Parton Scattering Scattered Parton Anti-Proton 1000 GeV Proton 1000 GeV Scattered Parton

7. CH “calorimeter jet” hadrons FH  EM “particle jet” Time “parton jet” Jet Production and Reconstruction Highest ET dijet event in Run I at DØ • Fixed cone-size jets • Add up towers • Iterative algorithm • Jet quantities:

8. High Energy Art

9. Forward Proton Detector - a series of momentum spectrometers that make use of accelerator magnets in conjunction with position detectors along the beam line Forward Proton Detector (FPD) • Quadrupole Spectrometers • surround the beam: up, down, in, out • use quadrupole magnets (focus beam) • Dipole Spectrometer • inside the beam ring in the horizontal plane • use dipole magnet (bends beam) • also shown here: separators (bring beams together for collisions) A total of 9 spectrometers composed of 18 Roman Pots

10. Castle Status • All 6 castles with 18 Roman pots comprising the FPD were constructed in Brazil, installed in the Tevatron in fall of 2000, and have been functioning as designed. A2 Quadrupole castle installed in the beam line.

11. FPD Detector Design • 6 planes per detector in 3 frames and a trigger scintillator • U and V at 45 degrees to X, 90 degrees to each other • U and V planes have 20 fibers, X planes have 16 fibers • Planes in a frame offset by ~2/3 fiber • Each channel filled with four fibers • 2 detectors in a spectrometer 17.39 mm V’ V Trigger X’ X U’ U 17.39 mm 1 mm 0.8 mm 3.2 mm

12. Detector Construction At the University of Texas, Arlington (UTA), scintillating and optical fibers were spliced and inserted into the detector frames. The cartridge bottom containing the detector is installed in the Roman pot and then the cartridge top with PMT’s is attached.

13. Detector Status • 20 detectors built over a 2+ year period at UTA. • In 2001-2002, 10 of the 18 Roman pots were instrumented with detectors. • Funds to add detectors to the remainder of the pots were obtained via an NSF MRI • grant in 2003 (should acknowledge funding from UTA REP, Texas ARP, DOE, • and Fermilab as well). • During the shutdown • (Sep-Nov. 2003), the final eight • detectors and associated readout • electronics were installed. • All 18 pots are routinely inserted • near the beam. A2 Quadrupole castle with all four detectors installed

14. Diffractive Topics and Students!

15. Research Possibilities for you? It’s possible, either in HEP or other areas for dedicated students (that is, will work for free!) Send me an e-mail, and we can discuss Now on to your regularly scheduled class