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HIGH Q 2 NC 98 e - p Analysis

HIGH Q 2 NC 98 e - p Analysis. ZEUS COLLABORATION MEETING 24/6/99. C. M. Cormack (RAL). Jason Breitweg, Ricardo Goncalo, Alexander Kappes, Amaya Lopez Duran-Viani Henning Schnurbusch, Holger Wieber. PRELIMINARY CROSS SECTIONS. RESULTS FROM A. KAPPES C.M. CORMACK. EVENT SELECTION.

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HIGH Q 2 NC 98 e - p Analysis

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  1. HIGH Q2 NC 98 e- pAnalysis ZEUS COLLABORATION MEETING 24/6/99 C. M. Cormack (RAL) Jason Breitweg, Ricardo Goncalo, Alexander Kappes, Amaya Lopez Duran-Viani Henning Schnurbusch, Holger Wieber PRELIMINARY CROSS SECTIONS RESULTS FROM A. KAPPES C.M. CORMACK • EVENT SELECTION DATA, CUTS, CORRECTIONS • DATA/MC CHECKS • PRELIMINARY CROSS SECTIONS • SYSTEMATIC CHECKS • SUMMARY

  2. Event Selection ALL 1998 - 1999 DATA * Run Range 30758 - 32906 END OF 1999 BITS USED : b12 1998 and b107 in 1999 • Excluded runs31728 - 31752 Noise 32125 - 32142 - Noise in BCAL 31892 - LASER 31893 - Test Trigger 31700 - LPS PROBLEM 30894, 31025, 31029 - EMPTY EVENT INFORMATION (NO ZES) Total Luminosity = 15.945 pb-1 “Preliminary number”

  3. THEORY + MOTIVATION HIGH Q2 SENSITIVITY TO Z0 EXCHANGE POTENTIAL EXTRACTION OF xF3 VALENCE QUARK DISTRIBUTIONS

  4. KINEMATIC CUTS: Q2 > 800.0 GeV2 LOWER BORDER OF LOWEST BIN RESTRICTED TO BCAL Yel <0.95 0. < xBJ < 1. 0. < y < 1. CUTS SELECTION CUTS: SINISTRA + EM Ee > 10 GeV -50 cm < z-vertex < 50 cm FOR THETA > 0.3 - TRACK MATCH DCA < 10 cm : TRACK WITH p > 5 GeV - 38 GeV < E-pz < 65 GeV FOR THETA < 0.3 - pT Electron > 30 GeV - 44 < E-pz < 65 GeV CONE ISOLATION < 5 GeV

  5. PRELIMINARY CROSS SECTIONS KINEMATIC RANGE: Q2 > 800 GeV2 0. < y < 1. 0. < x < 1. PRELIMINARY CROSS SECTIONS: , , Q2 > 10 000 GeV2

  6. Q2 >100GeV2 200k • Q2 > 400 GeV2 20k • Q2 > 1250 GeV2 20k • Q2 > 5000 GeV2 10k • Q2 > 20000 GeV2 10k KINEMATICS AND RECONSTRUCTION NOISE & CORRECTIONS Noise Suppression as applied in the Reconstruction and Hot cells removed using Mario Martinez’s routine RCALCORR 98 Dead Material Corrections Applied 97 MAP NON - UNIFORMITY CORRECTION 97 IN THE BCAL USED KINEMATIC RECONSTRUCTION Hadronic Reconstruction using CORANDCUT Using Double Angle Kinematics MONTE CARLO MC num98t0.1 e-p DJ 6.24 CTEQ4D, ARIADNE ALSO DJH CTEQ4D MEPS 320k - SYSTEMATIC

  7. SYSTEMATIC ERRORS SYSTEMATIC VARIATION 1. Electron Energy scale +/- 3 % 2. Hadronic Energy Scale +/- 3% 3. Variation of the electron smearing 9% +/- 1 % 4. Varying the lower E-pz cut +/- 2 GeV 5. Change yEL < 0.9 6. Vary Econe +/- 2 GeV 7. Vary pt/sqrt(Et) from 4 +/- 2 GeV 8. Vertex Reweighting on and off 9. Increase ZVTX + 10 cm 10. Acceptance using MEPS 11. Rescaling of 1st IR 12. DCA CUT 8. cm -2. cm 13. CAL THETA 14. SINISTRA - EM UNCERTAINTY IN LUMINOSITY 2.5 % NOT SHOW PLOTS >>>>>>>>>

  8. Acceptance, Efficiency and Purity

  9. Monte Carlo Used Num98t0.1 CTEQ4D ARIADNE FILES • Q^2 > 100 GeV^2 200k • Q^2 > 400 GeV^2 20k • Q^2 > 1250 GeV^2 20k • Q^2 > 5000 GeV^2 10k • Q^2 > 20000 GeV^2 10k 320 k MEPS Events Funneled 320 k Djangoh Events In Funnel - low priority 2.6 M High Et Photoproduction in production. Shared with CC People Diffractive MC for Low Q2 > 200 GeV After reprocessing

  10. CROSS CHECKS • Electron Energy Smearing 9% • 20 % IN QUADRATURE GAUSSIAN SMEARING WITH ZEUS QUOTED ELECTRON ENERGY UNCERTAINTY PLOTS >>>>>>>> • FPC | Energies in the FCAL INNER RING Numt0.1 Energies in FPC too Low Energy in the 1IR also too low in 98 ADD 6 % of FPC Energy is added to 1IR ? Energies In 1IR reweighted using: TREATED AS A SYSTEMATIC PLOT >>>

  11. SUMMARY TWO INDEPENDENT ANALYSES EXIST OF HIGH Q2 NC CROSS SECTION SINISTRA ANALYSES ARE IN GOOD AGREEMENT DIFFERENCES OF TYPICALLY LESS THAN 2% CROSS CHECK WITH EM IN GENERAL GOOD AGREEMENT WITH SM THE EFFECT OF THE Z0 CLEARLY SEEN AT HIGH Q2 THE ENHANCEMENT FROM Z0 CLEARLY SEEN IN THE ELECTRON DATA Q2 > 10 000 FUTURE PLANS DOUBLE DIFFERENTIAL CROSS SECTIONS CROSS CHECK OF HIGH Q2 F2 …… EXTRACT FIRST HIGH Q2 xF3 AND FINALLY THANKS ! >>>

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