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Neutral Current: Ongoing Systematic Studies and loose ends. Chris Cormack Alexander Kappes Henning Schnurbusch Matthias Moritz Ricardo Gonçalo. SFEW Review Meeting 4 th December 2001. Photoproduction normalisation: Henning
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Neutral Current: Ongoing Systematic Studies and loose ends Chris Cormack Alexander Kappes Henning Schnurbusch Matthias Moritz Ricardo Gonçalo SFEW Review Meeting 4th December 2001 • Photoproduction normalisation: Henning • First inner ring and hadronization + Checks of new MEPS sample: Ricardo Review Meeting 4th December 2001
Selection cuts: • DST bit 12 • Q2DA > 120 GeV2 • Elumi- < 2 GeV (avoid bremstrahlung) • 5 GeV < Elumi-e < 15 GeV (acceptance) • ET > 30 GeV • |Z-vertex| < 50 cm • EelectronCAL > 10 GeV Photoproduction normalisation Energy spectrum from Lumi-e detector for loose DIS cuts and Elumi-< 2GeV E-pZ distribution with loose DIS cuts: MC generated with Et>30GeV Review Meeting 4th December 2001
Photoproduction normalisation Herwig Et>30GeV + DJANGOH & Herwig Et>10GeV (direct PhP only) + DJANGOH Herwig Et>10GeV (direct PhP only) & Pythia 96/97 (some visible DIS contribution) Review Meeting 4th December 2001
Hadronization and FCAL Inner Ring From September Review Meeting: Ariadne reproduces the data except in FCAL 1st IR This affects low y / high x / low had Need a good systematic error estimation in IR: Now: Ariadne |Ariadne - MEPS| will be used as systematic error for several effects FCAL Inner Ring: several studies done - remove IR energy from DA calculations for had > 0.314rad ?(??????) - vary energy scale in IR ? - take cells for low had or do W cut à la 96/97 ? (problem with large syst. error) - Vary remnant parameters in MC? (no noticeable effect on en.flow) To do: Use all MC for better stats Redo properly with CureMyCalDoc • Remove IR energy from DA calculations for had > 0.314rad ? • Vary energy scale in IR ? • Take cells for low had or do W cut à la 96/97 ? • Vary remnant parameters in Monte Carlo ? • To do: • Use all MC for better stats • Redo properly with CureMyCalDoc Review Meeting 4th December 2001
Hadronization and FCAL Inner Ring Sources of systematic error (hard to disentagle): Combined systematic error determination: ? For most of the phase space: Ariadne |Ariadne - MEPS| Hadronisation (parton showers) ? Imprecise dead material map • Systematic for low y region: • Is the had measurement at high y affect by the very forward region ? • Island -> Cells splitting ? • WJB > 20 GeV cut ? • Ariadne |Ariadne - MEPS| - is this sufficient? Angular non-uniformities of detector response ? ? Modelling of remnant FPC-FCAL leakage & backscattering ? Review Meeting 4th December 2001
(Preliminary from Matthias & Henning) Eff = 50% but Syst Err = 140% (island splitting) Error > 50% Hadronisation at low y : Island -> cell splitting • Do sum over cells for islands in FCAL with radius < 30 cm: • For the reduced cross section, systematic errors around 2% except at low yDA • One good bin shows very large effect Review Meeting 4th December 2001
Old MEPS (e+p) islands New MEPS (e-p) islands Old MEPS (e+p) cells New MEPS (e-p) cells Checks of new MEPS sample Current MEPS sample was generated with Soft colour Interactions card ON New sample being generated for e-p: number of vertex refitted tracks now agrees with data Old and new sample seem to agree well in the hadronic energy flow: BUT Review Meeting 4th December 2001
Checks of new MEPS sample - R.G. Review Meeting 4th December 2001