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Inclusive Dijets in Low Bjorken- x. An Investigation of the low Bjorken- x breakdown of DGLAP. Tom Danielson University of Wisconsin. Main Issue: Low x DGLAP Breakdown. DGLAP: Ladder “k t – ordered” k t1 > k t2 > k t3 > …. BFKL: Scheme based on log(1/ x ) - PowerPoint PPT Presentation
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Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Tom DanielsonUniversity of Wisconsin
An Investigation of the low Bjorken-x breakdown of DGLAP
Inclusive Dijets in Low Bjorken-Inclusive Dijets in Low Bjorken-xxInclusive Dijets in Low Bjorken-Inclusive Dijets in Low Bjorken-xx
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Main Issue: Low Main Issue: Low xx DGLAP DGLAP BreakdownBreakdown
Main Issue: Low Main Issue: Low xx DGLAP DGLAP BreakdownBreakdown
Gluon ladder
DGLAP: Ladder “kt – ordered” kt1 > kt2 > kt3 > …
1
2
BFKL: Scheme based on log(1/x)
Well-suited to low-x events (forward jets) No kt-ordering of ladder
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Ground Work: Selecting EventsGround Work: Selecting EventsGround Work: Selecting EventsGround Work: Selecting Events
Issue 1: Detector vs. Generator level kinematics for MC
Ariadne with Q2min = 10 GeV2
True level x, Q2 plotted against xda and Q2da
calculated from zufos
True level y plotted against yjb calculated from zufos
Cuts applied progressively
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Initial DistributionsInitial DistributionsInitial DistributionsInitial Distributions
Almost no cuts jet finding on-line: needed cut to avoid electron being mistaken for jets.
-1 < <3 No jet Et cut – very few events lost
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Cut 1: 25 < QCut 1: 25 < Q22dada < 150 GeV < 150 GeV22Cut 1: 25 < QCut 1: 25 < Q22dada < 150 GeV < 150 GeV22
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Next cut: 10Next cut: 10-2-2 < < xx < 10 < 10-4-4Next cut: 10Next cut: 10-2-2 < < xx < 10 < 10-4-4
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Next Cut: .04 < yNext Cut: .04 < yjb jb <.7<.7Next Cut: .04 < yNext Cut: .04 < yjb jb <.7<.7
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Next cut: 35 < E – pNext cut: 35 < E – pz z < 65< 65Next cut: 35 < E – pNext cut: 35 < E – pz z < 65< 65
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Next cut: |zNext cut: |zvtxvtx| < 50 cm| < 50 cmNext cut: |zNext cut: |zvtxvtx| < 50 cm| < 50 cm
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Next cut: DIS03Next cut: DIS03Next cut: DIS03Next cut: DIS03
Electron energy cut Ee > 10 cuts no events
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Final Cut: Asymmetric EFinal Cut: Asymmetric ETT Cut on Cut on JetsJets
Final Cut: Asymmetric EFinal Cut: Asymmetric ETT Cut on Cut on JetsJets
Electron box cut eliminates no events.ET,1 > 7 GeV, ET,2 > 6 GeV
Dijets at low Bjorken-x, Tom Danielson, U. Wisconsin Wisconsin Group Meeting, 5 August 2004
Future PlansFuture PlansFuture PlansFuture Plans
• Immediate future:• Evaluate effectiveness of cuts
• Data/MC control plots
• After control plots:distributions
• Order jets in , plot distributions of trailing jet • Cross sections
• Possible measurements of between 2 leading ET jets