Standard AnalysisNtuple Variables
Introduction
The variables from the Analysis Ntuple are presented here grouped by tool. Within
each tool, variables are arranged roughly according to their position in the ntuple.
Unless otherwise noted, energy is in MeV, length is in mm, and angle is in radians.
Also, unless otherwised noted, the null value, that is, the value in the ntuple when there
is no calculated value for a given variable, is zero.
The variables may be of type Int, Float, or Double. Currently all but one are floats.
(EvtElaspedTime is a double.)
AdCValsTool Variables
Notes- Default Doca/ActiveDistance is -2000.
- Active distance is negative if a track is outside a tile, positive if inside.
- For variables called AcdNoXXX, "No" means "Number."
| Variable | Type | Description |
|---|---|---|
| AcdTotalEnergy | F | Total energy deposited in ACD |
| AcdTileCount | F | Number of tiles fired |
| AcdDoca | F | Nearest distance of any track from the center of any tile |
| AcdDocaTileEnergy | F | The deposited MC energy in the corresponding hit tile |
| AcdActiveDist | F | Largest active distance of any track to the edge of any tile |
| AcdActDistTileEnergy | F | The deposited MC energy in the corresponding hit tile |
| AcdGammaDoca | F | Distance of Gamma to the center of the nearest tile |
| AcdCornerDoca | F | Minimum Distance of Closest Approach to the corner side gaps |
| AcdActDistTop | F | Smallest active distance of any track to top tiles |
| AcdActDistSideRow[0...3] | F | Smallest active distance of any track to tiles in side row [0...3] |
| AcdNoTop | F | hit tile count for top |
| AcdNoSideRow[0...3] | F | Hit Tile count for side row [0...3] |
| AcdRibbonActDist | F | Smallest active distance to any ribbon (considered as a straight line of no thickness) |
| AcdTkrHitsCountTop | F | Count of the number of TkrClusters within a pre-defined distance (default: 250 mm) of the center of the hit top ACD tiles. |
| AcdTkrHitsCountR[0...3] | F | ditto for ACD tiles in side row [0...3] |
CalMipValsTool Variables
| Variable | Type | Description |
|---|---|---|
| CalMipNum | F | Total number of found mip-like tracks in the Cal |
| CalMip[X/Y/Z]0 | F | [x/y/z] coordinates of the energy centroid of the best track |
| CalMip[X/Y/Z]Dir | F | [x/y/z] direction cosines of the best track |
| CalMipD2edge | F | Distance of the best track from the nearest edge of the Cal |
| CalMipArcLen | F | Length of the best track (mm) |
| CalMipEcor | F | Mean vertical-eq1uvalent energy (MeV) of the best track, obtained by averaging the pathlength-corrected energies in each layer |
| CalMipEcorRms | F | RMS of CalMipEcor |
| CalMipChi2 | F | Chi-squared of the direction fit for the best track (combination of least squares in XZ and YZ planes) |
| CalMipErm | F | total energy (MeV) contained in a cylinder of 1 Moliere radius around the best track |
CalValsTool Variables
| Variable | Type | Description |
|---|---|---|
| CalEnergyRaw | F | Sum of the raw energies in all the crystals. Includes estimate of missed energy due to zero-supression. This replaces the variable CalEnergySum. NEW! |
| CalEnergyCorr | F | Cal Energy corrected layer-by-layer for edges and leakage. This replaces the variable CalEneSumCorr. NEW! |
| CalLeakCorr | F | Leakage correction: this is the contained fraction of the total energy after edge corrections. |
| CalEdgeCorr | F | Effective layer-by-layer edge correction mainly due to the gaps between Cal modules; multiplicative |
| CalTotalCorr | F | Global total correction. Includes effect due to dead material; multiplicative |
| CalCsIRLn | F | Total radiation lengths in crystals, integrated along the event axis (line connecting the first hit in the tracker to the CAL energy centroid) |
| CalTotRLn | F | Total radiation lengths in the CAL, integrated along the event axis. |
| CalCntRLn | F | Radiation lengths integrated along the event axis, up to energy centroid |
| CalLATRLn | F | Total radiation lengths integrated along the event axis (including the tracker). |
| CalDeadTotRat | F | Ratio of radiation lengths in dead material to CalTotRLn |
| CalDeadCntRat | F | Ratio of radiation lengths in dead material up to energy centroid, to CalCntRat |
| CalTPred | F | Model-predicted energy centroid in radiation lengths |
| CalDeltaT | F | Difference between measured and predicted energy centroids |
| CalTwrEdge | F | Distance of the entry point of the best track from the tower boundary, measured at the top of the CAL. |
| CalLATEdge | F | Closest distance of track 1, projected to the top of the CAL, to the edge of the CAL layer, taking non-square shape into account. This is essentially the old merit skirt variable. |
| CalEdgeEnergy | F | The sum of the raw energies in each crystal for which the energy centroid is within _deltaEdge (currently 50 mm) of the outside edge of one of the outside CAL modules. This is an attempt at a "anti-coincidence counter" for the CAL. |
| CalTwrEdgeCntr | F | Distance of the energy centroid from the nearest tower boundary. |
| CalGapFraction | F | Approximate fraction of the shower volumn which falls in inter-tower gaps. |
| CalTrackSep | F | Distance between impact points of two best tracks at CAL front face; zero if only one track |
| CalTrackDoca | F | Distance between the projected vertex (or track if only one track) and the energy centroid, evaluated at the z of the centroid. |
| CalTrackAngle | F | Angle between "gamma" direction in the tracker and direction of the CAL "track" |
| CalELayerN, N=0,7 | F | Energy deposited in layer N of the CAL |
| CalLyr0Ratio | F | Ratio of CalELayer0 to CalEnergyRaw |
| CalLyr7Ratio | F | Ratio of CalELayer7 to CalEnergyRaw |
| CalBkHalfRatio | F | Ratio of total energy in back half of CAL (layers 4-7) to CalEnergyRaw |
| CalXtalsTrunc | F | Number of CAL Xtals with > 1 of CalEnergyRaw (see CalXtalRatio) |
| CalXtalRatio | F | Ratio of number of Xtals with energy > 1% of CalEnergyRaw to total number of struck Xtals in the event. |
| CalXtalMaxEne | F | Maximum energy found in a single Xtal |
| CalLongRms | F | This is proportional to the length of the measured shower along the shower axis. It is determined by diagonalizing the matrix of the positions of the energy deposits, like an inertia tensor, but with energy substituted for mass, and taking the average of the two large eigenvalues. (Includes an ad-hoc correction for energy.) |
| CalLRmsAsym | F | The asymmetry of the two large eigenvalues above This should be close to zero, for a "typical" shower. |
| CalTransRms | F | rms of transverse position measurements. |
| CalMIPDiff | F | Difference between measured energy and that expected from a minimum-ionizing particle |
| CalMIPRatio | F | Ratio of measured energy to that expected from a minimum-ionizing particle |
| Cal[X/Y/Z]Ecentr | F | Energy centroid in [x/y/z] |
| Cal[X/Y/Z]Dir | F | [x/y/z] direction cosine of CAL "track" |
| Cal[X/Y]0 | F | [x/y] position of CAL "track" |
EvtValsTool Variables
These are calculated from combinations of the variables from different tools.NOTE
- All EvtEXxx variables are previous variables compensated for energy and angle
| Variable | Type | Description |
|---|---|---|
| EvtRun | F | Run number, copied from the event header NEW: replaces Run in the merit ntuple |
| EvtEventId | F | Sequence number of event in the run (as generated) NEW: replaces Event_ID in the merit ntuple |
| EvtElapsedTime | D | Elapsed time in seconds since t0 (for DC1: 18-July-2005, for the future: mission start 1-Jan-2001) |
| EvtEnergyCorr | F | Event energy formed by adding the corrected tracker energy (TkrEnergyCorr) to the layer-by-layer corrected cal. energy CalEnergyCorr. |
| EvtEnergyRaw | F | TkrEnergy + CalEnergyRaw |
| EvtDeltaEoE | F | (EvtEneryCorr - McEnergy)/ McEnergy. Was EvtMcEnergySigma |
| EvtCalEdgeAngle | F | Obsolete; replaced by CalTwrGap |
| EvtTkrEdgeAngle | F | Obsolete; replaced by Tkr1TwrGap |
| EvtLogEnergy | F | log10 of EvtEnergySumOpt, pegged between log10(20) and log10(50,000). Was EvtLogESum |
| EvtTkr1EFrac | F | Tkr1ConE/EvtEnergyCorr, roughly, fraction of energy carried by best track |
| EvtVtxKin | F | The vertex opening angle compenstated for the energy split between the tracks. |
| EvtVtxEAngle | F | VtxAngle*EvtEnergyCorr. Should be approx. constant. However an empirical compensation is provided below (see EvtEVtxAngle) |
| EvtTkrComptonRatio | F | Ratio of TkrTotalHits to twice the number of layers from the head of the best track to the bottom of the TKR |
| EvtETkrComptonRatio | F | EvtTkrComptonRatio, flattened in energy and cos(theta). Was EvtTkrEComptonRatio |
| EvtPSFModel | F | PSF expected from simple model; depends only on energy. |
| EvtETkr1Chisq | F | Tkr1Chisq, compensated for energy and angle. |
| EvtETkr1FirstChisq | F | Tkr1FirstChisq, compensated for energy and angle |
| EvtETkr1Qual | F | Tkr1Qual, compensated for energy and angle |
| EvtTkr1PSFMdRat | F | Ratio of errors from covariance matrix to EvtPSFModel |
| EvtECalTransRms | F | CalTransRms, compensated for energy and angle |
| EvtECalLongRms | F | CalLongRms, compensated for energy and angle |
| EvtECalLRmsAsym | F | CalLRmsAsym, compensated for energy and angle |
| EvtECalXtalRatio | F | CalXtalRatio, compensated for energy and angle |
| EvtECalXtalTrunc | F | CalXtalsTrunc, compensated for energy and angle |
| EvtECalTrackDoca | F | CalTrackDoca, compensated for energy and angle |
| EvtECalTrackSep | F | CalTrackSep, compensated for energy and angle |
| EvtEVtxAngle | F | EvtVtxEAngle, compensated for energy and angle |
| EvtEVtxDoca | F | VtxDOCA, compensated for energy and angle |
GltValsTool Variables
(Glt = GLAST Trigger)
| Variable | Type | Description |
|---|---|---|
| GltWord | F | Trigger word from the event header, based on digi information (null value: -1) The definition of the bits can be found in TriggerBits.h in the enums package. Here are the definitions as of Glast Release v7r2 (they are not b_ACDL = 0x01 ///> set if cover or side veto, low threshold |
| GltGemSummary | F | For Data, a copy of the GEM condtion summary; for MC, the same as calculated from the trigger (digi) information (null value: -1) The bits are defined in GemConditionsSummary.h in the enums package. Here are the definitions as of GlastRelease v7r2 (They are not expected to change.): ROI = 0x01 CNO = 0x10 |
| GltEventFlags | F | Event flags from Ebf |
| GltTower | F | Id of tower that triggered; if more than one, choose the tower with the highest triggered layer (null value: -1) |
| Glt[X/Y]Tower | F | [x/y] index of GltTower (null value = -1) |
| GltTotal | F | Number of possible triggers (a straight-through track in a single tower produces 13 potential triggers |
| GltNumTowers | F | Number of towers which trigger (crossing track) |
| GltType | F | Number of exposed sides for the triggered tower, i.e. 0 = central tower, 1 = side tower, 2 = edge edge tower, 4 = any single-tower setup |
| GltMoment | F | Do not use |
| GltZDir | F | Do not use |
McValsTool Variables
| Variable | Type | Description |
|---|---|---|
| McSourceId | F | Unique integer associated with each MC source type; from McEvent header replaces Mc_src_Id in merit ntuple |
| McId | F | StdHepId of primary (-13 = mu+, 22 = gamma, etc.) |
| McCharge | F | Charge of primary |
| McEnergy | F | Kinetic energy of the generated primary particle |
| McLogEnergy | F | log10(McEnergy) |
| McEFrac | F | Fraction of incident energy in highest-energy daughter |
| McOpeningAngle | F | Actual opening angle between the first and second daughters of the promary as generated, (For a primary photon, these will ordinarily be the electron and positron.) |
| McTkrExitEne | F | Attempt to calculate the total energy leaving the tracker volume |
| Mc[X/Y/Z]0 | F | [x/y/z] coordinate of photon conversion or charged particle origin |
| Mc[X/Y/Z]Dir | F | [x/y/z] direction cosine of primary particle |
| Mc[X/Y]Err | F | [x/y] (found) - [x/y] (Mc) (Mc position taken at the z of the found vertex or first hit) |
| McZErr | F | z(actual vertex or first hit) - McZ0 |
| Mc[X/Y/Z]DirErr | F | [x/y/z]dir (found) - [x/y/z]dir (Mc ) |
| McDirErr | F | Angle between found direction and Mc direction (radians ) |
| McTkr[1/2]DirErr | F | Angle between direction of [best/second] track and Mc direction (radians) |
TkrValsTool Variables
Notes:- Variables called Tkr1Xxx refer to the "best" track; those called Tkr2Xxx refer to the
second track. - For variables listed as Tkr[1/2]Xxx there are two versions in the ntuple, one for the best
and one for the second track. - The labels are not entierly consistent, but it's probably too disruptive to fix them at this
point. For example: TkrRadLength, TkrTrackLength, TkrTwrEdge refer to track 1.
Also, Tkr2Angle and Tkr2HDoca are quantities that depend on both tracks. - The variables associated with the second track are undefined if there is only one track!
Check TkrNumTracks before using these variables! In fact check TkrNumTracks
before using first-track variables, for the same reason.
General variables
| Variable | Type | Description |
|---|---|---|
| TkrNumTracks | F | Number of tracks found (Maximum is set by TkrRecon, currently 10) |
| TkrSumKalEne | F | Sum of Kalman energies (see TkrNKalEne, below) for the two best tracks |
| TkrSumConEne | F | Sum of the energies for the two best tracks, as assigned by the patrec energy tool |
| TkrEnergy | F | Energy in tracker, as determined from linear regression analysis of number of clusters |
| TkrEnergySum | F | Deprecated |
| TkrEnergyCorr | F | TkrEnergy corrected by TkrEdgeCorr |
| TkrEdgeCorr | F | Tracker edge correction. This may go away; it's an intermediate quantity |
| TkrHDCount | F | Number of unused clusters in top x-y layer of the best track within a radius of 30 mm, corrected for track angle (Used in PSF analysis and background rejection) |
| TkrTotalHits | F | Deprecated. Use TkrSurplusHCInside instead |
| TkrSurplusHitsInside | F | Number of clusters inside an energy- and angle-dependent cone centered on the reconstructed axis of the best track and starting at the head of track 1. Only hits in layers with at least one x and one y cluster in the tower are counted. |
| TkrSurplusHitRatio | F | Ratio of the number of hits outside the cone to the number inside. See TkrSurplusHitsInside |
| TkrThinHits | F | Number of clusters in the above cone in the thin-converter layers |
| TkrThickHits | F | Number of clusters in the above cone in the thick-converter layers |
| TkrBlankHits | F | Number of clusters in the above cone in the no-converter layers |
| Tkr2TkrAngle | F | Angle between first and second reconstructed tracks |
| Tkr2TkrHDoca | F | Distance between first and second track in the plane of the first hit on the first track. This is most useful if the two tracks are almost parallel, in which case the usual DOCA is poorly measured. |
Variables that exist for both best and second tracks
| Variable | Type | Description |
|---|---|---|
| Tkr[1/2]Chisq | F | Track chisquared |
| Tkr[1/2]FirstChisq | F | Track chisquared for first Tkr[1/2]FirstHits layers |
| Tkr[1/2]Hits | F | Number of clusters in track |
| Tkr[1/2]FirstHits | F | Number of initial track hits used to determine the starting direction |
| Tkr[1/2][First/Last]Layer | F | [First/Last] layer in track (layer 0 is the bottom of the tracker) |
| Tkr[1/2]DifHits | F | Difference between the number of x and y clusters associated with track |
| Tkr[1/2]Gaps | F | Total number of gaps in track |
| Tkr1FirstGapPlane | F | plane number of first gap on track 1 (This and the following X,Y pair can be used to find dead strips) |
| Tkr1[X/Y]Gap | F | [x/y] location of first gap on track 1 |
| Tkr[1/2]FirstGaps | F | Number of gaps in first Tkr1FirstHits layers on track |
| Tkr[1/2]Qual | F | Track "quality": depends on the number of clusters and chisquared of the track. Maximum is currently 64, can be negative if chisqared gets large. This is used primarily to order the tracks during patrec. It's not a good idea to cut on this variable! |
| Tkr[1/2]Type | F | These are the status bits from the trackign, containing
The definitions should be fairly stable. |
| Tkr[1/2]TwrEdge | F | Distance from tower edge of initial point (0 is halfway between the towers, increases towards center of tower) |
| Tkr[1/2]PrjTwrEdge | F | Distance from tower edge of track extrapolated to the layer upstream of the first layer (See Tkr1TwrEdge.) |
| Tkr[1/2]DieEdge | F | Distance from die (wafer) edge of initial point (0 is halfway between the dies, increases toward center of die) |
| Tkr[1/2]KalEne | F | Kalman energy of track 1; this is the energy determined |
| Tkr[1/2]ConEne | F | Energy from PatRec energy tool for track 1. The tool computes the total event energy and then partitions it between the first 2 tracks according to their Kalman energies and energy errors |
| Tkr[1/2]KalThetaMS | F | Multiple scattering angle (radians) referenced to first layer. The contributions from all the layers in the track are adjusted for the predicted energy in each layer, and weighted accordingly. So the result is sensitive to the particle type and the chosen energy-loss mechanism. |
| Tkr[1/2][X/Y/Z]Dir | F | Track [x/y/z] direction cosine |
| Tkr[1/2]Phi | F | Track phi, radians (direction from which particle comes, not particle direction!) range: (0, 2pi) |
| Tkr[1/2]Theta | F | Track theta, radians (direction ditto) |
| Tkr[1/2][X/Y/Z]0 | F | Track [x/y/z] position at first hit |
Variables that exist only for best track
| Variable | Type | Description |
|---|---|---|
| TkrRadLength | F | Radiation lengths traversed by the best track. This is from half- way thru the initial converter to the lowest bi-plane in the tracker, whether or not the track actually gets to the end. |
| TkrTwrEdge | F | The average distance of the best track from the "edge" of each tray, weighted by radiation lengths traversed. (The edge is a plane halfway between the towers. |
| TkrTrackLength | F | Distance between the start of the best track and the grid, along the track axis. |
| Tkr1TwrGap | F | Length of track in nominal intertower gap, currently set to 18 mm. Can be a small as zero if track exits through bottom of tracker, and as large as the intertower gap, if track crosses to adjacent tower. |
| Tkr1ThetaErr | F | Error on the measurement of theta |
| Tkr1PhiErr | F | Error on the measurement of phi. |
| Tkr1ErrAsym | F | Tkr1SXY/(Tkr1SXX + Tkr1SYY) |
| Tkr1CovDet | F | Determinant of the error matrix, but normalized to remove the dependence on cos(theta) |
| Tkr1S[XX/YY] | F | [x-x/y-y] element of the covariance matrix; square of error on [x/y] |
| Tkr1SXY | F | x-y element of the covariance matrix; covariance |
| Tkr1ToTFirst | F | ToT of first hit on best track (All ToT's are adjusted for pathlength in the measuring and non-measuring directions in the strip, and for the strip width.) |
| Tkr1ToTAve | F | Average ToT for the hits on the best track |
| Tkr1ToTTrAve | F | Average ToT for the hits on the best track, excluding the largest and smallest |
| Tkr1ToTAsym | F | Asymmetry between last two and first two ToT's for the best track |
| Tkr1ChisqAsym | F | Asymmetry between last two and first two track-segment delta-chisquared's |
| Tkr1SSDVeto | F | Number of silicon planes between the top of the extrapolated track and the first plane that has a hit near the track. Only planes that have wafers which intersect the extrapolated track are considered. No checks for dead strips, etc. are made (yet!). Can be used as a back-up for the ACD. |
| Tkr1CoreHC | F | Number of clusters within a roughly cylindrical region ) (default radius 10 mm) around the hits in each plane between the first and last on the best track, excluding the clusters that belong to the track itself |
| TkrUpstreamHC | F | The number of hits in a cylinder (default radius 150 mm) up to 4 layers thick above the head of the first track. |
| Tkr1CORERatio | F | the ratio of Tkr1CoreHC and Tkr1Hits |
VtxValsTool Variables
| Variable | Type | Description |
|---|---|---|
| Vtx[X/Y/Z]Dir | F | [x/y/z] direction cosine of the (1st) vertex |
| VtxPhi | F | Azimuthal angle of vertex, radians (direction of source, not flight direction!) Range: (0,2pi) |
| VtxTheta | F | Polar angle of vertex, radians (ditto direction) |
| Vtx[X/Y/Z]0 | F | [x/y/z] coordinate of vertex; if the two tracks making up the vertex are nearly parallel, the coordinates of the vertex may become very large. |
| VtxAngle | F | Angle between the two tracks of the vertex (radians) |
| VtxDOCA | F | Distance of closest approach between the two tracks |
| VtxHeadSep | F | Distance between the heads of the two tracks |
| VtxStatus | F | Summary of track composition and topology. See TkrVertex.h in the
|
| VtxQuality | F | Vertex quality parameter used to order the possible vertices and select the best one. Should generally not be used in analysis. |
| VtxChisq | F | The covariant chi-squared for the pairing of the tracks. |
| VtxS[1/2] | F | Distance of DOCA point from head of track [1/2] |
| VtxAddedRL | F | The additional radiation lengths prior to the first measured silicon strip hit at the vertex location. New! |
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| Last updated by: Chuck Patterson 02/24/2006 |