DØ QCD: Past, Present, and Future

E

Andrew Brandt, University of Texas at Arlington

Physics SeminarMay 7, 2004Jefferson Lab

A1U A2U

P2DP1D

P

Pbar

LMVC

Tevatron at Fermilab

p p

Run I ( 1992 - 1997 ) :

s =1.8 TeV

Run II ( 2001 - ? ) :

s =1.96 TeV

Batavia, Illinois

Main Injector & Recycler

Tevatron

Booster

p p

p source

Chicago

CDF

CDF

DØ

DØDØ

SMTSMT

SMT

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

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

Parton-Parton Scattering

Described by QCD.

Anti-Proton1000 GeV

Proton1000 GeV

Scattered Parton

Scattered Parton

1x

2x

1 2

proton c.o.m. energy 1.96 TeV

ˆ parton c.o.m. energy squared

s

s x x s

q

Tim

ep p

q g

K

“par

ton

jet”

“par

ticle

jet”

“cal

orim

eter

jet”

hadrons

CH

FH

EM

Highest ET dijet event in Run I at DØHighest ET dijet event in Run I at DØ

0.69 GeV, 472E

0.69 GeV, 475E21

T

11T

0.7R

),(η 00 ),( Fixed cone-size

jetsAdd up towers

Iterative algorithm

Jet quantities:

Fixed cone-size jets

Add up towers

Iterative algorithm

Jet quantities:

0.7R

towerT

jetT

i

EE

0.7R

towerT

jetT

i

EE

,,ET ,,ET

Jet Production and ReconstructionJet Production and Reconstruction

High Energy Art

Forward Proton Detector

Forward Proton Detector (FPD)

• Quadrupole Spectrometers• surround the beam: up, down, in, out• use quadrupole magnets (focus beam)

- a series of momentum spectrometers that make use of accelerator magnets in conjunction with position detectors along the beam line

• 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

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.

Castle StatusCastle Status

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

0.8 mm

3.2 mm

1 mm

17

.39 m

m

17.39 mm

UU’

XX’

VV’

Trigger

Detector ConstructionDetector ConstructionAt 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.

• 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 withall four detectors installed

Detector StatusDetector Status

Diffractive Topics and Students!

Student (Year) Institute Subject Data Sample (In hand)

Michael Strang (2005) UTA Diffractive jets 2003 (Y) (graduated Sunday Aug. 14!)

Tamsin Edwards (2005) Manchester Diffractive Z (gaps) 2003 (Y)

James Monk (2006) Manchester Double Pomeron+jets

(gaps+quad?)

2004 (Y)

Renata Rodrigues (2007) UERJ Inclusive

Double Pomeron

2005-2006 (N)

Ana Carolina de Jesus (2007) UERJ Diffractive J/psi (gaps+quad?)

2003-2005 (Y)

Helena Malbouisson (2007) UERJ Diff. Struc. (dipole) 2004-2005 (Y)

Luis Mendoza (2007) Bogotá Diffractive W, Z (gaps+dipole)

2004-2005 (Y)

Murilo Rangel (2007/8) UFRJ Double Pomeron+jets

(gaps+quad)

2005-2006 (N)

Vlatislav Hynek (2007/8) CTU Diff. Struc, or DN/DT (quad)

2005-2006 (N)

Research Possibilities for you?

It’s possible, either in HEP or other areas for dedicatedstudents (that is, will work for free!)

Send me an e-mail, and we can discuss

Now on to your regularly scheduled class