A First DC2 Analysis with New Recons DC1 Recap Recon Re-write Review TkrRecon CalRecon Good Energy Analysis PSF Analysis THIS IS A PROGRESS REPORT ALL ANALYSIS ARE PRELIMINARY

DC1 Recap Eff. = 82% Bad-Cal = 4.5% Cuts: 1/1 Ratio 95/68 > 3 Meets SR Events Eff.: 94.5% Cuts: 3/2 Events Eff.: 52.3% Cuts: 3/4 Events Eff.: 19.1% Cuts: 2/1 An extensive analysis was performed to optimize PSF and energy resolution while maintaining the maximum Aeff. This was the first complete analysis done using the Geant 4 Simulation (previous Glast Analysis used the Gismo simulation) Bad-Cal = 4.5% Eff. = 82%

Background Rejection in DC1 3 Classes of Background after selection for good energy and direction reconstruction Prob. g > .5 Upward moving events Earth Limb events Downward moving events Prob. g > .9 A Classification Tree analysis was constructed allowing cutting on the probability that an event was a g (vs. Background) However – to meet the Science Req. for Background contamination – the remaining Aeff was lower then the goal (it did meet the Sci. Req.)

Conclusions from DC1 Major Effort was Launched to completely re-write The Status of the Reconstruction in GLAST was marginal 1) The code had been patch, re-patched, etc. many times 2) The code had become needlessly complex and essentially un-maintainable 3) The algorithms (particularly for the Calorimeter) were undeveloped Major Effort was Launched to completely re-write the Tracker and Calorimeter Recon 1) Emphasis on uniformity and simplicity 2) Migrate related task to one area 3) Re-vamp and re-assess poorly functioning algorithms (esp. Vertexing and Calorimeter)

TDS Classes Condensed and Simplified: Tracker Recon Re-write TDS Classes Condensed and Simplified: External Controls Control Name Internal Variable Def. Value Description MinEnergy m_minEnergy 30. Min. energy to use for setting search regions SigmaCut m_sigmaCut 9.0 Sigma cut for picking up points FirstTrkEnergyFrac m_1stTkrEFrac .8 First track energy fraction MinTermHitCount m_termHitCnt 16 Min. no. of hits on best track to terminate search MaxNoCandidates m_maxCandidates 10 Max. allowed number of candidate tracks MaxChisq m_maxChiSqCut 40. Max allow Combo Pat. Rec. Chisq. (1st fit) NumSharedFirstClusters m_hitShares 6 Number of first clusters which can be shared MaxNumberTrials m_maxTrials 50 Max. number of trial candidates to test FoVLimit m_PatRecFoV .19 Minimum cos(theta) for track trials MinCosKink m_minCosKink .7 Minimum cos(theta) for a track kink MaxTripletRes m_maxTripRes Max. un-normalized residual for first 3 TkrPoints TkrFitHit TkrFitMatrix TkrFitPar TkrFitPlane TkrFitTrackBase TkrKalFitTrackBase TkrKalFitTrack TkrPatCand TkrPatCandHit TkrRecInfo TkrTrackTab TkrTrackParams TkrTrackHit TkrTrack Program architecture simplified

New Vertex Algorithm Vertex Location Combining Tracks Multivariate Averaging: Put Vertex at Radiator Mid-Point Preferred Solution If 2 Tracks share the same first hit W RADIATOR SSD PLANE SUPPORT PANEL Found Tracks Put Vertex DOCA Point SUPPORT PANEL where Pi are the parameter vectors of the combination (Pair) and tracks (P1 and P2) and Ci are the covariance matrices where Next Best Solution If DOCA location of 2 tracks lies before 1st Hit W RADIATOR SSD PLANE All Other Case Put Vertex at Z location of start of the 1st Track Found Tracks The parameter vectors are (x, Sx, y, Sy)

CalRecon Re-write 2) Better Background Rejection Cuts 1) Put GLAST’s Fracture Energy Back Together 1 GeV g Thin Radiator Hits Gap Between Tracker Towers Thick Radiator Hits Blank Radiator Hits Gap Between CAL. Towers Calorimeter Xtals Leakage out CAL. Back 2) Better Background Rejection Cuts Shower Shape parameters 3) Move code to where it belongs! AnalysisNtuple CalRecon

CalRecon Re-write (cont.) A Major Change: Replace Layer-by-Layer Analysis with Energy-Moments Energy Moments: Same as Classical Mech. Mass moments with energy replacing mass (see Goldstein) (first used by S. Ritz in GLAST) Long. Moment Trans. Moment LSQ Fit to Layers Moments

Good Energy Analysis But First: The New Data Sets Initial Cuts: - Major effort by many people - Took a couple of shots to get right - 1.5x106 All Gamma* run 23-June-2005 - 6 x106 Orbit-Average Background run 24-June-2005 - All data run on SLAC Batch Farm available at GLAST ftp site - These are the first large data sets using new Recons Initial Cuts: CalEnergyRaw > 5 MeV and CalCsIRLn > 4 rad. len. 2) Tkr1ZDir < -.2 (FoV) color range: 0 - 150 Pruning Selections: 1) TkrNumTracks > 0 standard mode 2) TkrNumTracks = 0 Cal-Only Events! *All Gamma: 2p str. , 18 MeV – 180 GeV, 1/E Spectrum

Energy Assessment EvtDeltaEoE = Top plots show dep. on MC parameters was EvtMcEnergySigma Top plots show dep. on MC parameters Bottom plots show dep. on Recon parameters

Good Energy CT Analysis Data divide into Energy Ranges using CalEnergyRaw LowCal MedCal HiCal CalEnergyRaw < 350 MeV 350 - 3500 MeV CalEnergyRaw > 3500 MeV

Energy CT Details Low CAL Produce a set of variables that are ~independent of cos(q) and E Parametric function of Tkr1ZDir and EvtLogEnergy Define Class "GoodEnergy" & "BadEnergy" GoodEnergy: (will explore dependence on this) 2) Derive a CT for each of the EvtEnergyRaw Bins Low CAL

more Energy CT Details Med CAL High CAL

Energy CT Dependencies Since the energy resolution is improved – try more restrictive definition of "Good Energy" 100 80 60 20 40 100 80 60 20 40 100 80 60 20 40 Eff. DC1 Choice Select this one NOISE Expected Behavior Anomaly Use of Tkr1TotTrAve in Cal Low CT This is part of a problem at High Energies .... more later What's happening here?

Preliminary DC2 Energy Resolution Integrated Over FoV On Axis DC1 Resolution DC1 Resolution DC2 Resolution DC2 Resolution High Energy Deficit caused by Pat. Rec. Confusion! Aeff x DW = 4.02 m2-str Aeff x DW = 2.76 m2-str

Root Cause of Hi E Deficit Pictures and Words.... Incoming g Event #6 Bad Cal Dir These events come from Old CalRecon but effect remains. First attempt to fix problem: USE CAL DIRECTION 100 GeV g Event #9 Bad Cal Dir Incoming g Missed Track 100 GeV g Event #6 Bad Cal Dir Clearly there's more work to do here! Missed Track

A First PSF Analysis for DC2 Strategy: Divide and Conquer! Split Events in Thin and Thick Conversion locations For Events with > 1 Tkr. Vertices decide whether or not to use vertexed solution Example: Thin Radiator – Vertex CT

More PSF CT Details Strategy: Divide and Conquer! 3) Find and tag (a la probability) Events with large PSFs 4) Finally – add a knob to describe quality of reconstruction - Using a REGRESSION TREE

Preliminary DC2 PSFs DC1 DC2 Integrated over FoV On Axis 2.6 46.2 Sel. 1 Sel. 2 Sel. 3 Sel. 4 PSF68(100MeV) 4.7 4.1 3.6 3.0 4.2 3.8 3.3 2.6 PSF95/PSF68 4.4 2.3 2.2 3.2 Rel. Eff. (%) 100 94.5 52.3 19.1 95.2 74.0 46.2

DC2 Background Rejection Nothing has been done with the recently run data. (only became available late last Friday) But – Here's is a peek – Preemptory cuts: 1) GoodEnergy.Prob > .25 2) AcdDOCA > 250 3) Only Thin Radiator Events Analyzed so far Data: 5.1x106 Orbit Ave. Bkg. .75x106 All Gamma 15642 Events 942 Events (Good News)

more DC2 Background Rejection

more DC2 Background Rejection Energy & Angle Compensate CalTransRms Note: In AnalysisNtuple all variables beginning with EvtE..... are previously defined variables which have been compensated for log(E) and cos(q) dependencies.

Conclusions The 1st DC2 Workshop has already accomplished 90+% its goals! - look at all the work it stimulated! The Recon re-writes show good improvements in - Energy Reconstruction - PSF - New Variables to Reject Background The (first) large data samples are providing the next level of insight in the Recons - TkrRecon need more work in the area of very High Energy reconstructions - CalRecon needs MIP finding and more work to refine moments analysis (emphasis on directions)