Status of Reconstruction Studies for a Realistic Detector Ron Cassell SiD Workshop Nov. 15, 2010

Outline The simulated realistic detector: sidloi3 Reconstruction: UIPFA Current performance: jet energy resolution Additional realism: Hcal skins 2

3 Sidloi3: changes from sid02 Trackers – individual silicon sensors, realistic hit digitization. (See Rich Partridge talk last workshop) EcalBarrel - 12 overlapping staves, some tiny dead areas at borders. EcalEndcap – 12 sided polyhedron, no module borders. Ecal – 31 layers, extra 250 micron air gap per layer HcalBarrel – 12 modules, 40 layers, some empty areas at module borders. HcalEndcap – 12 sided polyhedron, no module borders, 45 layers. MuonBarrel – 8 modules, some empty areas at module borders. MuonEndcap – 8 sided polyhedron, no module borders. Hadronic interaction model in G4 changed from sid02 runs.

Wired event display 4

UIPFA Same reconstruction code for sid02 and sidloi3, except for tracking Driver. Many comparisons are made using fake tracking, due to some tracking problems. Still some problems with calibration, clustering and association compared to sid02 Total effect of these problems on jet energy resolution and dijet mass resolution smaller than potential gains in algorithm work. 5

Recent Algorithm changes DTClusters combined across Ecal/Hcal borders : eliminates penalty for different DTCluster when doing track/cluster association. Initial mip and muon finding rewritten : some improvement in performance, runs 70 times faster. 6 Fraction +- 2 layers: Old – 77.1% New – 82.3% Single muons: eff to reconstruct 1 muon and nothing else Muon E = 5,10,20,50,100 GeV

Known problems Tracking: forward inefficiencies, extreme cpu on some events, > 1 track from same particle. Some clustering problems across the Ecal module borders remain. Both Ecal and Hcal borders lead to as yet uncorrected phi dependence in calibration, visible in jet reconstruction. 7

Compare jet energy resolution with selected phi cut. Overlaps occur at discreet phi. Cut events with jet direction near that phi, and compare energy resolutions. 8

Single neutral hadrons in sidloi3 Example of uncorrected phi dependence in the sidloi3 detector. Effect s of overlapping Ecal staves and gap along Hcal border are both visible. 9

Jet Energy Resolution and Dijet Mass Resolution in sidloi3 dM/M (rms90): sid02 – 4.13% sidloi3 – 4.32% dM/M (gauss): sid02 – 5.26% sidloi3 – 5.48% 10

Hcal skins Study by Lauren Gilbert Compared projective and non-projective skins by removing hits in simple cylindrical geometry.(sid02) Measured effect of 5mm and 10mm skins with fully simulated skins in sidloi3 and UIPFA reconstruction. Found similar degradation from proj/nonproj in sid02. Found level of effect in sidloi3 same order as other phi effects. 11

Single neutral hadrons in sid02: projective vs non- projective gaps 12 With single simulation of sid02 detector, approximate hcal gaps by removing hits and then reconstructing, comparing projective vs non-projective gaps with 20 GeV neutral hadrons.

Projective vs non- projective gaps in qqbar events in sid02 With single simulation of sid02 detector, approximate hcal gaps by removing hits and then reconstructing, comparing projective vs non-projective gaps. 13

Full simulation and reconstruction in sidloi3 detectors Compare detectors with hcal skins of 0,5mm,10mm, using full reconstruction with the UIPFA. No corrections or recalibrations were used. 14

Reconstruction for the DBD Need to solve tracking problems. Need to implement corrections for additional “realism”. Run on sample at 1 TeV cm to identify additional problems. Verify algorithm improvements carry over to sidloi3.

Summary 16 We can reconstruct events from a more realistic detector simulation well enough to see the effects of the realism. There is considerable work needed to be ready for the DBD reconstruction. The degradation in performance going to a more realistic simulation is considerably smaller than the difference between SiD/UIPFA and ILD/Pandora for the LOI. The benchmark results for the LOI were similar.