where do we stand with the recommendations of the review panel ? tancredi carli (cern) 1

Where do we stand with the recommendations of the review

panel ?Tancredi Carli

(CERN)

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A Phd-student from Tel Aviv started to work on thatWill be counted as author qualification taskWriting out of calorimeter cells already tested

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Work on-going within the G4 team.To be tested: CHIPS model with G493 expected for December 09

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The E/P work is getting more organised: e.g. common development of analysis codeExpression of interest from more groups. Plans for dedicated analysis meeting in JanuarydESD work has settled for p<10 GeV (within the minimum bias DPD)For p>10 GeV: need to rely on AOD…XXXNo work done HLT triggers should be done

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Now new work on this issueGenerally more effort on forward region is needed.

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Atlas simulation will be time-dependent: see C Young in BarcelonaDead and noisy channels, trigger menu, background, beam conditionsTime dependent calibrations, e.g. luminosity dependent correction not yet addressed(e.g. pile-up).

The benchmarks are proposed, but not yet finalized: see Ariels twiki page XXXJet performance package being rewrittenHope to have first working version in JanuaryCommon samples with ready to use jet collections for 2010 are under discussion

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This is generally agreed within the jet/Etmiss group:Jet are calibrated to the “particle level”. In addition, we will provideanalysis dependent corrections.

We have a framework how to provide special analysis dependent correctionsWe have an idea who to determine underlying event corrections (from gamma-jet)and discussed hadronisation/fragmentation correction (from MC)However, this is more a physics analysis issue

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Some work on the relation of jet and Etmiss calibration has been performed(see October Jet/Etmiss meeting). However, the focus was the use ofthe jet energz scale correction that is by default not applied in Etmiss. In-situ corrections not yet tried out.Working (with top group) on performance study of various calibration streamsapplied via JetCalibToolsMore work on Etmiss should follow

Work on-going to define shower correction better:1) Calorimeter showering corrections 2) out-of-jet cone particlesProposal available to decouple showering from jet response

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We have agreed to the need of keeping 3 basic collections (for early data)1) topo-cluster 2) topo-tower 3) tower without noise suppressed

Performance comparisons are under way For 3) we study different possibilities: a) No negative noise, b) include negative tower as “ghost” in jet finding, subtract energy from jet c) using tower noise tool

Aim is to conclude in dedicated meeting 8.12.2009Warning: we are running option a) presently

This problem has recently been solved. When noise suppression is used, the jet area is effectively reduced and this has to be taken into account.

Still some problems seen in Forward region and for certainPile-up scenariosCorrection works in all cases to few percent.

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Work done by Pisa group on Eprime method without fitting:

http://indico.cern.ch/getFile.py/access?contribId=0&resId=0&materialId=slides&confId=66754


No conclusion yet, if this has an advantage over other methods

Fit functions and binning have been evaluated in direct balance and MPF method

Within the MPF method, the logarithmic parameterisation has been replacedby a power-law. http://indico.cern.ch/getFile.py/access?contribId=1&resId=0&materialId=slides&confId=66751The differences are small.


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There has been some effort to study systematic effects on gamma/jet balancee.g. changing selection cuts, reweighting photon spectrum etc.However, a toy MC has not been developed Should be doneQuite comprehensive systematic studies on gamma-jet balance are here:


http://indico.cern.ch/getFile.py/access?contribId=12&resId=1&materialId=slides&confId=48779http://indico.cern.ch/getFile.py/access?contribId=0&resId=0&materialId=slides&confId=66754

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We plan to add the forward region in the di-jet balance method and treatthen the difference to the central region as systematic uncertainty.Work on that is on-going.

There also has been some study on the MPF response in the forward region

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MC samples with systematics, like physics lists, changed dead-material etchave been produced for mc09 5 TeV. Similar exercise to be done for 3.5 TeV

We have produce sample with different physics list, changed dead material, noiseSome results are available, more work is needed.

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This has been studied for the dijet eta intercalibration (needs update with most recent menu)

For the gamma-jet trigger is ok. Present plan is to have DPD with no prescale


No bias is observed when far away from trigger threshold (loss in statistics)Up to 5% uncertainty introduced, if trigger turn on is not correct needs work

Gamma-jet back-ground has been studiedwithin direct gamma/jet balance and MPF

A large dijet sample for background studieshas been launched by Jet/Etmiss and Egamma(for mc08) in November+ Work ongoing to replace simple cuts on hard scattering pt by event weight,e.g. pt-5

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Comprehensive studies of on flavour dependence in all calibration schemes are available


Trigger studies not yet done.


Lot of progress on layer fraction method. Includes now also jet width.Gives competitive jet performance then global and local cell weighting

Biases on the correction chain have been tested: ATL-PHYS-INT-2009-051

Comparison of sequential and full 3-dim correction available.Results the same within 1%

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We had two dedicated meetings on that. Many interesting results, but the requestedsamples were late. We have ideas how to calculate the systematics.We have nothing complete. We have to work on that.

Next aim: Have a complete systematic uncertainty estimate beforewe have gamma-jet data available(see also recommendation by jet walk through committee)

Started work to propagate in-situ uncertainties:

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There is substantial progress on robust cosmic rejection in particular in presence of pile-up

Only plan exist for a software framework for physics analysis should be finalised.

No work done in this direction

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Calo monitoring now included in jet/etmiss shifts. Work on details still neededCaloMon, Lar and Tile expert participate in Jet/Etmiss savannah bug reports

We have compared 2008/2009 commissioning data.The noise is well understood.We are still working on some observed differences in the high energy dataLatest results in October meeting

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Electrons and muons do not pose a problem for the new Etmiss code.This issue has been addressed in the October jet/Etmiss meetingWe see improvements in Etmiss resolution when applying the full jet energy scale for jets(but not for W+jets?). Plan is to repeat this when response and showering are decoupled

We have madecomprehensive studies of energy showering out of the calorimeter jet

This addresses the em-scale.More work is neededfor global cell weighting (weight derivation)and local cells weighting (out-of-cluster corrections)

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The DPD content is finalizedThe list of samples need is also clear (see Koji talk earlier)

Recently, a lot of developments from trigger side.We followed this, but did not looked in detailed at the consequence for jet performance

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Taken on board.

This was always the plan.Work is on-going for the MPF method and the direct photon balance

Done inhttp://indico.cern.ch/getFile.py/access?contribId=0&resId=0&materialId=slides&confId=66754

Summary

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We have made progress in many areas. However, looking back to the report, there are still many open pointswhere more work is needed.To achieve something it takes always more time than anticipated.

We have now the first data. Nevertheless it is important that wecontinue to work according to our plan and also follow therecommendation. The real aim is to have a defendable jetcalibration in place for first physics results to be shown in conferences.

Many thanks to the committee member for putting together thisvery useful report.

where do we stand with the recommendations of the review panel ? tancredi carli (cern) 1

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