Visual Checks of the Reconstruction using Atlantis Gary Taylor (UCSC) 4/3/2003 Outline Tracking in the inner detector at design luminosity Reconstruction of secondary vertices Calorimeter clustering and jets Tracking in the muon system Future plans

Check track reconstruction in difficult design luminosity event Selected event has two high pt (>560GeV) jets ( DC1dataset 2045) Luminosity 1034 Silicon space points 27,000 TRT hits 240,000 Reconstructed tracks 1,200 Reconstructed in 20 minutes

2D projections of Inner Detector data not very useful at design luminosity (TRT -ve barrel only)

Explanation of the fh and V-Plot projections r = rMax V-Plot Draw each space point twice at F,h+k*(r-rMax) and F,h-k*(r-rMax) 3D information For tracks can judge f h pt (slope of V arms) charge ( L -ve V +ve) f low p, -ve r = 2 cm h Distorted V’s track not from IP high p, +ve

V-Plot silicon space points Fh calorimeters

Filtering of space points available inside Atlantis Filter space points with a histogram based technique which selects hits consistent with tracks originating from the primary vertex. Time = 1 sec/event ATLAS note in preparation

Filtered hits xKalman tracks True tracks 225 GeV 34 tracks 410 GeV 20 tracks 165 GeV 28 tracks 270 GeV

Tracks lost in core of central jet Unreconstructed true tracks Unused filtered hits … and true tracks

Lost tracks in forward jet True tracks not reconstructed All unused filtered hits Good unused filtered hits on true tracks

Zoom next track feature – allows easy checking of tracking True tracks – association not yet available for reconstructed

Clusters from Silicon Strips (work in progress) stereo clusters track space point rf clusters Need … cluster-to-track association (stereo clusters wrong in 6.0.0!) z r

Identifying secondary vertices Look for a group of nearby kinked V’s in the VPlot True tracks Reconstructed tracks D B

Reconstructed and simulated secondary vertices in XY plane (t-bln) 3s error ellipse Primary Reconstructed tracks True tracks

Secondary vertex region best displayed in abstract 3D Box Ellipses represent track error (1s) Plane containing primary vertex Plane containing secondary vertex secondary vertex primary vertex

Single electron – 30 GeV pT (DC1) LAr Presampler Pt=29.3 GeV E =31.2 GeV Cell geometry LAr Layer 2 LAr Layer 3 LAr Layer 1 Track (enters LAr here) Area a E Island (guides eye)

Cell clustering and Jet reconstruction – AtlFast (DC1- QCD event) Details of cell clustering Cells coloured by cluster (Area a E) Jet (Area a E) ? E= 13 GeV SE= 347 GeV Bug ?

Muon tracking with Moore – work in progress Need to follow muon tracks in magnetic field MDT RPC

V-Plot allows comparison Comparison of muon and inner detector track fits f p = 28 GeV Dp = 5 GeV Df = 1.5 deg Dh = 0.02 muon tracks Inner detector tracks p = 25 GeV Dp = 4 GeV Df = 1 deg Dh = 0.01 V-Plot allows comparison of f, h and pt h

Future plans (near term) Dependent on Athena add tracks from iPatRec add reconstructed track-to-hit association follow Moore tracks in B field add Moore track-to-hit association add data from CSC’s fully implement data from AtlFast Independent of Athena move to latest muon geometry improve display of calorimeters (esp FCAL and ITC)

Conclusions many aspects of the reconstruction may be checked using Atlantis much more available soon (Athena stability permitting) followed by new public release users and their feedback/requests are very welcome Special thanks to Jon Couchman (Access to data from Athena –JiveXML) Hans Drevermann (Ideas and advice)