Trijets in Neutral Current Deep Inelastic Scattering

1
Trijets in Neutral Current Deep Inelastic
Scattering
A Proposal for Studies Using the 1998 -2000 Data
Liang Li University of Wisconsin
2
96-97 Data Offline Cuts Start from Dijets Cuts

• Detector Acceptance and Efficiency yJB gt
  0.04 positron found with E gt 10 GeV
  vertex cut -50cm lt z lt 50 cm positron
  position cut X gt 14 cm or Y gt 14 cm
• Signal Selection
• 38 GeV lt E-Pz lt 65 GeV A well found
  track with p gt 5 GeV DCA lt 15 cm yEL lt
  0.95

Physics and Kinematic Requirement 100
GeV2 lt Q2 lt 10000 GeV2 Three jets found
using KTCLUS algorithm ? lt 2.0
ETLAB gt 5 GeV
New requirement added to Dijets
ET,1BRT gt 8 GeV, ET,2BRT gt 5 GeV , ET,3BRT gt 5
GeV
3
First Look at DIS Trijets (DA)
ReconstructedQ2, x, y by Double Angle method
Q2
x
Use LO Ariadne for all MC
OK agreement between data and Ariadne
y
Area normalized
4
First Look at ZEUS DIS Trijets

• Conclusions
• First glance at DIS Trijets at ZEUS shows
  reasonable agreement between data Ariadne
• LO Ariadne MC used from Dijet Analysis without
  changes -gt a good starting point
• Plans
• Calculate cross sections and compare in detail
  with other QCD calculations and different MC
  programs (LO NLO)
• Add 1998-2000 data for more statistics
• Explore systematic uncertainties