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Ricardo GoncaloReview Meeting 4th December 20011 Neutral Current: Ongoing Systematic Studies and loose ends SFEW Review Meeting 4 th December 2001 Chris.

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Presentation on theme: "Ricardo GoncaloReview Meeting 4th December 20011 Neutral Current: Ongoing Systematic Studies and loose ends SFEW Review Meeting 4 th December 2001 Chris."— Presentation transcript:

1 Ricardo GoncaloReview Meeting 4th December Neutral Current: Ongoing Systematic Studies and loose ends SFEW Review Meeting 4 th December 2001 Chris Cormack Alexander Kappes Henning Schnurbusch Matthias Moritz Ricardo Gonçalo Photoproduction normalisation: Henning First inner ring and hadronization + Checks of new MEPS sample: Ricardo

2 Ricardo GoncaloReview Meeting 4th December Energy spectrum from Lumi-e detector for loose DIS cuts and E lumi-  < 2GeV E-p Z distribution with loose DIS cuts: MC generated with Et>30GeV Selection cuts: DST bit 12 Q 2 DA > 120 GeV 2 E lumi-  < 2 GeV (avoid bremstrahlung) 5 GeV < E lumi-e < 15 GeV (acceptance) E T > 30 GeV |Z-vertex| < 50 cm E electron CAL > 10 GeV Photoproduction normalisation

3 Ricardo GoncaloReview Meeting 4th December Photoproduction normalisation Herwig Et>10GeV (direct PhP only) & Pythia 96/97 (some visible DIS contribution) Herwig Et>30GeV + DJANGOH & Herwig Et>10GeV (direct PhP only) + DJANGOH

4 Ricardo GoncaloReview Meeting 4th December Hadronization and FCAL Inner Ring 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 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: - 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 Now: Ariadne  |Ariadne - MEPS| will be used as systematic error for several effects FCAL Inner Ring: several studies done

5 Ricardo GoncaloReview Meeting 4th December Hadronization and FCAL Inner Ring Sources of systematic error (hard to disentagle): FPC-FCAL leakage & backscattering Hadronisation (parton showers) Imprecise dead material map Angular non-uniformities of detector response Modelling of remnant For most of the phase space: Ariadne  |Ariadne - MEPS| Systematic for low y region: Is the  had measurement at high y affect by the very forward region ? Island -> Cells splitting ? W JB > 20 GeV cut ? Ariadne  |Ariadne - MEPS| - is this sufficient? Combined systematic error determination:

6 Ricardo GoncaloReview Meeting 4th December (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 y DA One good bin shows very large effect

7 Ricardo GoncaloReview Meeting 4th December 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 Old MEPS (e+p) islands New MEPS (e-p) islands Old MEPS (e+p) cells New MEPS (e-p) cells

8 Ricardo GoncaloReview Meeting 4th December Checks of new MEPS sample - R.G.


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