combined longitudinal weight extraction and intercalibration s.paganis ( wisconsin ) with k.loureiro...

Combined Longitudinal Combined Longitudinal Weight Extraction and Weight Extraction and

IntercalibrationIntercalibration

S.Paganis (S.Paganis (WisconsinWisconsin))withwith

K.Loureiro (K.Loureiro (WisconsinWisconsin), T.Carli (), T.Carli (CERNCERN))and input fromand input from

F.Djama(Marseille), G.Unal, D.Zerwas F.Djama(Marseille), G.Unal, D.Zerwas (Orsay)(Orsay)

Physics Plennary, CERN, Nov-4-2004Physics Plennary, CERN, Nov-4-2004

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Some ReferencesSome References Atlas LAr Group, NIM A500 (2003) 202, NIM A500 (2003) Atlas LAr Group, NIM A500 (2003) 202, NIM A500 (2003)

178.178. Atlas LAr Group, Linearity and Uniformity LAr EMC Test-Atlas LAr Group, Linearity and Uniformity LAr EMC Test-

Beams (in preparation)Beams (in preparation) G.Graziani, ATL-LARG-2004-001G.Graziani, ATL-LARG-2004-001 N.Kerschen, “New Results from e/N.Kerschen, “New Results from e/”, Freiburg ATLAS ”, Freiburg ATLAS

Overview Week Oct-5-04Overview Week Oct-5-04 F.Djama, ATL-LARG-2004-008F.Djama, ATL-LARG-2004-008 D.Fournier, M.Kado, L.Serin (talks in LAr weeks)D.Fournier, M.Kado, L.Serin (talks in LAr weeks) ATL-COM-CAL-2004-002ATL-COM-CAL-2004-002 M.Boonekamp: Drell-Yan talk in this plennary.M.Boonekamp: Drell-Yan talk in this plennary. Our note to be submitted (ATL-LARG Nov/04)Our note to be submitted (ATL-LARG Nov/04)

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A short overview of cell and A short overview of cell and e/e/ corrections corrections

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EMC Cell Energy ReconstructionEMC Cell Energy Reconstruction

C = (ADC_to_DAC)C = (ADC_to_DAC)(from ramps)(from ramps)

(DAC_to_Volts)(DAC_to_Volts)(17bit ADC-> (17bit ADC-> 38.14738.147V/digit)V/digit)

(Volts_to_(Volts_to_A)A)(from injection resistor)(from injection resistor)

((A_to_MeV) A_to_MeV) (t(tdriftdrift*W)/e *W)/e 1/SF1/SF

5,1

PEDESTALADCOFi

iirec cE

From Geant 4 (averaged Sampling Fractions):Accordion: SF = 0.167, ||<0.8Presampler: SF = 0.05

Energy Deposited = (1/SF)*(visible Energy)Energy Deposited = (1/SF)*(visible Energy)

G.Unal: Overview of Calibration and Reconstruction in Athena, LAr week, 6-Sep-04

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Corrections at the cell levelCorrections at the cell level

non-linear corrections to ADC->DAC (non-linear corrections to ADC->DAC (not in not in AthenaAthena))

Intercalibration Weights (Intercalibration Weights (not in Athenanot in Athena)) 1 weight per region (~0.2x0.4) is expected

HV corrections (skeleton in Athena)HV corrections (skeleton in Athena)

Capacitance variation in EMEC (Capacitance variation in EMEC (not in not in AthenaAthena))

Lead thickness corrections (Lead thickness corrections (not in Athenanot in Athena))

LAr purity and Temperature Variation LAr purity and Temperature Variation corrections (corrections (not in Athenanot in Athena))

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Corrections at the cluster level Corrections at the cluster level 9.0.09.0.0

S-shape correctionS-shape correction Corrects the reconstructed position of a cluster along

-modulation-modulation Corrects the energy as a function of the cell impact

point in offset in offset in

Corrects the cluster position along -modulation-modulation

Corrects the energy as a function of the cell impact point in

out-of-cone correctionout-of-cone correction Corrects the energy for losses in the lateral direction

Correction for upstream material effectsCorrection for upstream material effects Through:

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Some of these corrections are Some of these corrections are being re-evaluatedbeing re-evaluated New Energy parametrizations (upstream New Energy parametrizations (upstream

effects), effects), D.Fournier, L.Serin, M.Kado, T.CarliD.Fournier, L.Serin, M.Kado, T.Carli

out-of-cone will be absorbed in overall scaleout-of-cone will be absorbed in overall scale

Longitudinal leakage correction can be done Longitudinal leakage correction can be done through a mean shower depth parametrization through a mean shower depth parametrization which is which is dependent ( dependent (Graziani, Orsay groupGraziani, Orsay group))

Soft electrons (see Derue+Kaczmarska’s talk)Soft electrons (see Derue+Kaczmarska’s talk)

Photons? the expectation is that an overall few % scale Photons? the expectation is that an overall few % scale factor (factor ( dependent) is needed on top of the existing dependent) is needed on top of the existing weights and should be obtained from MC (tested weights and should be obtained from MC (tested against TBeam). Detailed studies are needed (K. against TBeam). Detailed studies are needed (K.

Loureiro, Slovakia meeting).Loureiro, Slovakia meeting).

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LAr upstream material LAr upstream material effects and Intercalibrationeffects and Intercalibration

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e/gamma: two serious e/gamma: two serious problemsproblems Upstream Material Corrections: Upstream Material Corrections: extraction of EMC extraction of EMC

longitudinal weights which correct the e/longitudinal weights which correct the e/ energy for energy for effects due to the material upstream of the EM effects due to the material upstream of the EM CalorimeterCalorimeter

Intercalibration: Intercalibration: equalization of response of different equalization of response of different physical regions of the EM Calorimeter physical regions of the EM Calorimeter

Monte Carlo: several effects not includedMonte Carlo: several effects not included LAr purity and temperature variations Mechanical and Electronics effects High Voltage (i.e. missing lines, gap variations etc) other

Such effects (even after correcting for them at Such effects (even after correcting for them at the cell level), affect the resolution constant the cell level), affect the resolution constant term, giving rise to the problem of term, giving rise to the problem of intercalibration and its in-situ monitoring intercalibration and its in-situ monitoring during ATLAS data taking.during ATLAS data taking.

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InterCalibration InterCalibration

ATLAS Requirement: 0.3% uniformity in 448 ATLAS Requirement: 0.3% uniformity in 448 regions (regions (x x = 0.2 x 0.4) of the EMC = 0.2 x 0.4) of the EMC

This gives a 0.7% resolution constant termThis gives a 0.7% resolution constant term

First Intercalibration with cosmic muons (ATL-First Intercalibration with cosmic muons (ATL-GEN-2004-001 and L.Serin et al, LAr week, GEN-2004-001 and L.Serin et al, LAr week, Sep-2003)Sep-2003)

Use middle layer -> S/B = 7, peak E=250MeV, large fluctuations

Expect a uniformity better than 0.5% but, Need high statistics (~10k muons per cell?) Need to control response with time (months) Assume it works: we need to monitor it during Physics

Runs.

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In-situ intercalibration using Z-In-situ intercalibration using Z->ee>ee In-situ, people propose Z->ee (In-situ, people propose Z->ee (F.Djama+TDRF.Djama+TDR))

But, to extract LAr weights (LW) which correct But, to extract LAr weights (LW) which correct for upstream material effects also need for upstream material effects also need electrons.electrons.

The two problems (LW+IC) are coupled !The two problems (LW+IC) are coupled !

For PDF uncertainties and E-scale issues, see For PDF uncertainties and E-scale issues, see M.Boonekamp, Mass and Energy Scale using Z M.Boonekamp, Mass and Energy Scale using Z events, Atlas Week June 2004. Also at this events, Atlas Week June 2004. Also at this plennary.plennary.

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LAr Longitudinal Weights LAr Longitudinal Weights (assume Intercalibrated EM Calorimeter)(assume Intercalibrated EM Calorimeter)

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Longitudinal weights calculated using:Longitudinal weights calculated using:

In 100 In 100 bins from 0 to 2.5 bins from 0 to 2.5 Currently through single electronsCurrently through single electrons

First step, But not just an academic exercise: study the parametrizations found in TBeam; find the weights that give optimum linearity and resolution.

8.2.0: sim+dig+rec (already out-of-date!)8.2.0: sim+dig+rec (already out-of-date!) In-situ: from Z (1 per sec), W (10/s)In-situ: from Z (1 per sec), W (10/s) CAUTION: the MC doesn’t simulate miss- CAUTION: the MC doesn’t simulate miss-

inter-calibration (must also be solved in situ)inter-calibration (must also be solved in situ)

e-based Longitudinal EMC e-based Longitudinal EMC weightsweights

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EMC Longitudinal Weights (8.2.0 EMC Longitudinal Weights (8.2.0 Recon)Recon)

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Calorimeter without upstream material Calorimeter without upstream material correctionscorrections

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Calorimeter after application of Long. Calorimeter after application of Long. WeightsWeights

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Scale and Uniformity for 50GeV Scale and Uniformity for 50GeV electronselectrons

Before Corrections New Weights

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Energy Resolution for 100 Energy Resolution for 100 bins bins

Before Corrections New Weights

A small improvement per bin is seenEresol = 1.6% In the central barrel regionEresol = 1.5% in the Test-Beam 2002

(1X0 of upstream material)

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Effect on Z->eEffect on Z->e++ee--

From DC2 Samples

dc2.002896.pyt_h130_4ldc2.002896.pyt_h180_4l

/castor/cern.ch/atlas/project/dc2/

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Combined Longitudinal Combined Longitudinal Weight Extraction and Weight Extraction and

Intercalibration Intercalibration

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Combined MethodCombined Method

Expect the intercalibration weights Expect the intercalibration weights to be to be absorbed in the overall scale: absorbed in the overall scale:

To do this we can extend the long. weights to To do this we can extend the long. weights to be be dependent. dependent.

In the following we apply a In the following we apply a ±5% ±5% miscalibration miscalibration in (in (xx==0.2x0.4)0.2x0.4) regions of the calorimeter regions of the calorimeter and recalculate the weights in ~800 and recalculate the weights in ~800 bins. bins.

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electrons: Miscalibrated Calorimeter electrons: Miscalibrated Calorimeter (±5%)(±5%)

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electrons: Response after combined electrons: Response after combined methodmethod

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Look at 50GeV: uniformityLook at 50GeV: uniformity

Before Corrections New Weights

A better than 0.2% Uniformity is found(crack region excluded)

EMB-EC crack

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Effect on Z->eEffect on Z->e++ee--

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Caveats: how well can we do this with Caveats: how well can we do this with W->eW->e and Z->ee ? and Z->ee ?

Method possible with single electrons Method possible with single electrons of known energyof known energy

pp->Z+X->ee+X, with Z mass constrainpp->Z+X->ee+X, with Z mass constrain pp->W+X->e+X, where e isolated relies pp->W+X->e+X, where e isolated relies

on trackingon tracking

To be done:To be done: Recalculation of the weights for versions 9.x.x Weights for all cluster types (3x7, 5x5, etc)

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SummarySummary We discussed two important problems that EM We discussed two important problems that EM

Calorimetry has to deal with during data taking: Calorimetry has to deal with during data taking: intercalibration and corrections for losses in upstream intercalibration and corrections for losses in upstream material. When electrons are used, the two problems material. When electrons are used, the two problems are coupled.are coupled.

An extension of the LAr Calorimeter weights to include An extension of the LAr Calorimeter weights to include intercalibration effects was studied using electrons.intercalibration effects was studied using electrons.

A better than 0.2% uniformity was found, excluding the A better than 0.2% uniformity was found, excluding the Barrel-EndCap crack region.Barrel-EndCap crack region.

In-situ, the method has the advantage of using a single In-situ, the method has the advantage of using a single data-sample for both corrections, however its data-sample for both corrections, however its performance must be tested with pp->Z+X->ee+X performance must be tested with pp->Z+X->ee+X events. events.