The merit ntuple contains all the variables found in the Analysis Ntuple, with a few additional. They're split up into several groups below. Text in RED or GREEN contains queries or comments between the perpetrators; users should ignore these. (But you won't, I'll bet!)
Text in BLUE contains notes to the user.
First, the variables generated in merit. (Note: Since this file is documentation for AnalysisNtuple, it is not guaranteed to be up-to-date for merit.) The names here are likely to change... underscores removed, consistent prefixes added, maybe "IM" changed to "Event"...
| Run | Run number |
| Event_ID | Event sequence number (as generated) in the run |
| MC_src_Id | Unique integer associated with each MC source ("Id" here and "ID" above should be made consistent) |
| elapsed_time | elapsed time in seconds since t0 (for DC1: 18-July-2005) |
| FilterStatus_HI* | High order 17 bits of filter status word; these are the veto bits. If this word is non-zero, the event was vetoed by the OnboardFilter code. |
| FilterStatus_LO* | Low order 15 bits of filter status word; these give status of the OnboardFilter for this event.* |
| IMgoodCalProb | Classification tree probability that Cal energy is well measured |
| FT1EventID | RunNo*(number of events in file) + EventNo |
| FT1Energy | Should be EvtEnergySumOpt; original issue uses Tkr1ConEne and TkrSumConEne |
| FT1Theta | Theta of event in detector frame (next few items in degrees, 666 if no tracks) |
| FT1Phi | Phi of event in detector frame |
| FT1Ra | Right Ascension of event |
| FT1Dec | Declination of event |
| FT1ZenithTheta | Earth zenith angle of event |
| FT1EarthAzimuth | Earth azimuth of event |
| FT1ConvPointX | X conversion point of event, whether single track or vertex, 999 if no tracks |
| FT1ConvPointY | ditto Y |
| FT1ConvPointZ | ditto Z |
| FT1ConvLayer | conversion layer of event, -1 if no tracks |
| IMvertexProb | Classification tree probability that the vertex gives a better measure of the direction than the best track alone |
| IMcoreProb | Classification tree probability that the event is in the core of the PSF |
| IMpsfErrPred | Classification tree prediction of the PSF for this event, normalized to the 68% point predicted from an analytic model. That is, "1" means that this event is likely to have the nominal PSF; a lower number means that the PSF is likely to be better than nominal. |
| IMgammaProb | Classification tree prediction of the probability that this event is a gamma rather than a background event. |
* See http://www-glast.slac.stanford.edu/software/core/tempstuff/filter.htm for definitions of the bits in these words.
Then the variables from the Analysis Ntuple, arranged by tool, and by sequential order within each tool. 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. (I'll fix these as I find them.)
| McId | StdHepId of primary (-13 = mu+, 22 = gamma, etc.) |
| McCharge | charge of primary |
| McEnergy | Kinetic energy of the generated primary particle NEW definition!! |
| McEFrac | fraction of incident energy in highest-energy daughter |
| McLogEnergy | log10(McEnergy) |
| McX0 | x coordinate of photon conversion or charged particle origin |
| McY0 | ditto y |
| McZ0 | ditto z |
| McXDir | x direction cosine of primary particle |
| McYDir | ditto y |
| McZDir | ditto z |
| McXErr | x (found) - x (Mc) (Mc position taken at the z of the found vertex or first hit) |
| McYErr | ditto y |
| McZErr | z(actual vertex or first hit) - McZ0 NEW!! |
| McXDirErr | xdir (found) - xdir (Mc) |
| McYDirErr | ditto y |
| McZDirErr | ditto z |
| McDirErr | angle between found direction and Mc direction (radians) |
| McTkr1DirErr | angle between direction of best track and Mc direction (radians) |
| McTkr2DirErr | angle between direction of second track and Mc direction (radians) |
| GltWord | trigger word from the event header (null value is -1) |
| GltTower | Id of tower that triggered; if more than one, choose the lowest (null value is 18) |
| GltXTower | x index of GltTower (null value = -1) |
| GltYTower | y index of GltTower (null value = -1) |
| GltLayer | first layer of trigger in GltTower (this is recon layer; 0 is at the top!) |
| GltTotal | number of possible triggers (a straight-through track in a single tower produces 13 potential triggers |
| GltNumTowers | number of towers which trigger (crossing track) |
| GltType | number of exposed sides for the triggered tower, i.e. 0 = central tower, 1 = side tower, 2 = edge edge tower. This number is 4 for the EM. |
| GltMoment | Please ignore for now |
| GltZDir | ditto |
| TkrNumTracks | number of tracks found (Maximum is set by TkrRecon, currently 10) |
| TkrSumKalEne | sum of Kalman energies for the two best tracks |
| TkrSumConEne | sum of the energies for the two best tracks, as assigned by the patrec energy tool |
| TkrEnergy | energy in tracker, as determined from linear regression analysis of number of clusters |
| TkrEnergySum | energy in tracker, as determined by counting up clusters and associated radiation lengths. This is historical; it will probably go away, so don't use it! |
| TkrEnergyCorr | TkrEnergy corrected by TkrEdgeCorr |
| TkrEdgeCorr | tracker edge correction. This may go away; it's an intermediate quantity |
| TkrHDCount | number of unused clusters in top x-y layer of track |
| TkrTotalHits | number of clusters "near" the best track. This may go away; it's an intermediate quantity |
| TkrThinHits | number of clusters in the thin converter layers. ditto! |
| TkrThickHits | number of clusters in the thick converter layers. ditto! |
| TkrBlankHits | number of clusters in the no-converter layers. ditto! |
| TkrRadLength | 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 | The average distance of the track from the "edge" of each tray, weighted by radiation lengths traversed. (The edge is a plane halfway between the towers. |
| TkrTrackLength | distance between the start of the track and the grid, along the track axis. |
| Tkr1Chisq | Track 1 chisquared |
| Tkr1FirstChisq | Track 1 chisquared for first Tkr1FirstHits layers |
| Tkr1Hits | Track 1 number of clusters |
| Tkr1FirstHits | number of initial track-1 hits that determine the starting direction |
| Tkr1FirstLayer | first recon layer in track 1 |
| Tkr1DifHits | difference between the number of x and y clusters associated with track 1 |
| Tkr1Gaps | Track 1 total number of gaps |
| Tkr1FirstGaps | Track 1 number of gaps in first Tkr1FirstHits layers on track 1 |
| Tkr1Qual | Track 1 quality: depends on the length and chisquared of the track. Maximum is currently 64, can be negative if chisqared gets large.u |
| Tkr1Type | PatRec type for
track 1: integer with digits abc (i.e. 231) a: 1 = blind, 2 = cal-seeded b: 1 = patrec minimun energy, 2 = Kalman energy, 3 = constrained energy c: number of leading hits upstream of first x-y pair |
| Tkr1TwrEdge | Distance from tower edge of initial point (0 is halfway between the towers, increases towards center of tower) |
| Tkr1PrjTwrEdge | Distance from tower edge of track extrapolated to the layer upstream of the first layer (See Tkr1TwrEdge.) |
| Tkr1DieEdge | Distance from die (wafer) edge of initial point (0 is halfway between the dies, increases toward center of die) |
| Tkr1TwrGap | 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. |
| Tkr1KalEne | Kalman energy of track 1; this is the energy determined from the multiple scattering along the track (goes like 1/E). Since a track with no scattering is possible, this energy is artificially limited to 100 GeV. |
| Tkr1ConEne | energy from PatRec energy tool for track 1. This tool computes the total event energy and then partitions it between the first 2 tracks according the their Kalman energies and energy errors |
| Tkr1KalThetaMS | 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. |
| Tkr1XDir | Track 1 x direction cosine |
| Tkr1YDir | ditto y |
| Tkr1ZDir | ditto z |
| Tkr1Phi | Track 1 phi, radians (direction from which particle comes, not particle direction!) range: (0, 2pi) |
| Tkr1Theta | Track 1 theta, radians (direction ditto) |
| Tkr1X0 | Track 1 x position at first hit |
| Tkr1Y0 | ditto y |
| Tkr1Z0 | ditto z |
| Tkr1ThetaErr | error on the measurement of theta |
| Tkr1PhiErr | error on the measurement of phi. |
| TkrErrAsym | Tkr1SXY/(Tkr1SXX + Tkr1SYY) |
| Tkr1CovDet | determinant of the error matrix, but normalized to remove the dependence on cos(theta) |
| Tkr1SXX | x-x element of the covariance matrix; square of error on x |
| Tkr1SXY | x-y element of the covariance matrix; covariance |
| Tkr1SYY | y-y element of the covariance matrix; square of the error on y |
| Tkr1ToTFirst | ToT of first hit on best track (all ToT's are adjusted for pathlength in the non-measuring direction in the strip) NEW!! |
| Tkr1ToTAve | Average ToT for the hits on the best track NEW!! |
| Tkr1ToTTrAve | Average ToT for the hits on the best track, excluding the largest and smallest NEW!! |
| Tkr1ToTAsym | Asymmetry between last two and first two ToT's for the best track NEW!! |
| Tkr1ChisqAsym | Asymmetry between last two and first two track-segment delta-chisquared's NEW!! |
| Tkr1SSDVeto | number of hit layers before start of track NEW!! |
| Tkr2Chisq | Track 2 chisquared |
| Tkr2FirstChisq | Track 2 chisquared for first Tkr2FirstHits layers |
| Tkr2Hits | Track 2 number of clusters |
| Tkr2FirstHits | number of initial track-2 initial hits that determine the starting direction. |
| Tkr2FirstLayer | first recon layer in track 2 |
| Tkr2DifHits | difference between number of x and y clusters associated with track 2 |
| Tkr2Gaps | Track 2 total number of gaps |
| Tkr2FirstGaps | Track 2 number of gaps in first Tkr2FirstHits layers |
| Tkr2Qual | Track 2 quality (See Tkr1Qual) |
| Tkr2Type | PatRec type
for track 1: integer with digits abc (i.e. 231) a: 1 = blind, 2 = cal-seeded b: 1 = patrec minimun energy, 2 = Kalman energy, 3 = constrained energy c: number of leading hits upstream of first x-y pair |
| Tkr2TwrEdge | Distance from tower edge of initial point (0 is halfway between the towers, increases towards center of tower) |
| Tkr2PrjTwrEdge | Distance from tower edge of track extrapolated to the layer upstream of the first layer (See Tkr1TwrEdge.) |
| Tkr2DieEdge | Distance from die (wafer) edge of initial point (0 is halfway between the dies, increases toward center of die) Not much used; may go away. |
| Tkr2KalEne | Kalman energy of track 2 (See Tkr1KalEne) |
| Tkr2ConEne | energy from PatRec energy tool for track 2. Note: this tool computes the total event energy and then partitions it between the first 2 tracks according the their Kalman energies and energy errors |
| Tkr2KalThetaMS | 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. |
| Tkr2XDir | Track 2 x direction cosine |
| Tkr2YDir | ditto y |
| Tkr2ZDir | ditto z |
| Tkr2Phi | Track 2 phi, radians (direction from which particle comes, not particle direction!) Range: (0, 2pi) |
| Tkr2X0 | Track 2 x position at first hit |
| Tkr2Y0 | ditto y |
| Tkr2Z0 | ditto z |
| VtxXDir | x direction cosine of the (1st) vertex |
| VtxYDir | ditto y |
| VtxZDir | ditto z |
| VtxPhi | azimuthal angle of vertex, radians (direction of source, not flight direction!) Range: (0,2pi) |
| VtxTheta | polar angle of vertex, radians (ditto direction) |
| VtxX0 | x coordinate of vertex; if the two tracks making up the vertex are nearly parallel, the coordinates of the vertex may become very large. |
| VtxY0 | ditto y |
| VtxZ0 | ditto z |
| VtxAngle | angle between the two tracks of the vertex (radians) |
| VtxDOCA | distance of closest approach between the two tracks (Spelling may change to "Doca" at some point after the Collaboration Meeting) |
| VtxHeadSep | distance between the heads of the two tracks |
| VtxS1 | distance of DOCA point from head of track 1 |
| VtxS2 | ditto track 2 |
| VtxDocaWgt | empirical weight factor for VtxDoca, goes from zero to one. Docas large compared to expectation generate low weights. The width seems to be constant with E... shouldn't it decrease with E? (being checked) |
| VtxHSWgt | ditto VtxHeadSep. |
| VtxS1Wgt | ditto VtxS1 |
| VtxT12Wgt | ditto VtxAngle |
| VtxT2QWgt | ditto quality factor for 2nd track. High quality yields high weight. |
| VtxTotalWgt | Logarithm of the product of VtxT12Wgt, VtxT2QWgt and VtxHSWgt. Is always negative (log of a number less than 1) |
| CalEnergySum | Sum of the raw energies in all the crystals |
| CalEnergyCorr | Cal Energy corrected globally for edge and leakage |
| CalEneSumCorr | Cal Energy corrected layer-by-layer for edges and leakage |
| CalEnergy_LL_Corr | Last-layer-corrected energy. Currently valid between 0 and 26 degrees, and between 1 and 50 Gev. Returns a negative number when out of range Remove underscores at some agreed-upon time! |
| CalLeakCorr2 | Approximation for leakage correction. |
| CalEdgeSumCorr | Effective layer-by-layer edge correction; multiplicative |
| CalTotSumCorr | Effective global correction; multiplicative |
| CalCsIRLn | Total radiation lengths in crystals, integrated along the trajectory of the first track |
| CalTotRLn | Total radiation lengths integrated along trajectory of first track |
| CalCntRLn | Radiation lengths integrated along trajectory of first track, up to energy centroid |
| CalDeadTotRat | Ratio of radiation lengths in dead material to CalTotRLn |
| CalDeadCntRat | Ratio of radiation lengths in dead material up to energy centroid, to CalCntRat |
| CalTPred | Model-predicted energy centroid in radiation lengths |
| CalDeltaT | Difference between measured and predicted energy centroids |
| CalTwrEdge | Distance of energy centroid from tower boundary ( >~30 mm is inside active CAL) |
| CalLATEdge | 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. |
| CalTENrm | Cosine of angle between event trajectory and normal to nearest side of the CAL module (evaluated at the energy centroid). Used to characterize the effect of the calorimeter gaps on the energy deposit |
| CalTrackSep | Distance between impact points of two best tracks at CAL front face; zero if only one track |
| CalTrackDoca | Distance between the projected vertex (or track if only one track) and the energy centroid, evaluated at the z of the centroid. |
| CalTwrGap | length of track in intertower gaps |
| CalELayer0 | energy deposited in layer 0 |
| CalELayer1 | ditto layer 1 |
| CalELayer2 | ditto layer 2 |
| CalELayer3 | ditto layer 3 |
| CalELayer4 | ditto layer 4 |
| CalELayer5 | ditto layer 5 |
| CalELayer6 | ditto layer 6 |
| CalELayer7 | ditto layer 7 |
| CalLyr0Ratio | ratio of CalELayer0 to CalEnergySum |
| CalLyr7Ratio | ratio of CalELayer7 to CalEnergySum |
| CalBkHalfRatio | ratio of total energy in back half of CAL (layers 4-7) to CalEnergySum |
| CalXtalsTrunc | number of CAL Xtals with > %1 of CalEnergySum (see CalXtalRatio) |
| CalXtalRatio | Ratio of number of Xtals with energy > 1% of CalEnergySum to total number of struck Xtals in the event. |
| CalLongRms | rms of longitudinal position measurements |
| CalLRmsRatio | CalLongRms divided by the raw calorimeter energy |
| CalTransRms | rms of transverse position measurements |
| CalMIPDiff | difference between measured energy and that expected from a minimum-ionizing particle |
| CalMIPRatio | ratio of measured energy to that expected from a minimum-ionizing particle NEW!! |
| CalXEcentr | energy centroid in x (Spelling may change to CalXCentr or CalXCenter) |
| CalYEcentr | ditto y |
| CalZEcentr | ditto z |
| CalXDir | x direction cosine of CAL "track" |
| CalYDir | ditto y |
| CalZdir | ditto z |
| CalX0 | x position of CAL "track" |
| CalY0 | ditto y |
| CalZ0 | ditto z |
| AcdTotalEnergy | total energy deposited in ACD |
| AcdTileCount | number of tiles fired |
| AcdDoca | nearest distance of any track from the center of any tile |
| AcdActiveDist | nearest distance of any track to the edge of any tile |
| AcdGammaDoca | distance of Gamma to the center of the nearest tile |
| AcdActDistTop | smallest active distance of any track to top tiles |
| AcdActDistSideRow0 | smallest active distance of any track to tiles in side row 0 (topmost) |
| AcdActDistSideRow1 | ditto side row 1 |
| AcdActDistSideRow2 | ditto side row 2 |
| AcdNoSideRow0 | Hit Tile count for side row 0 |
| AcdNoSideRow1 | ditto side row 1 |
| AcdNoSideRow2 | ditto side row 2 |
| AcdRibbonActDist | smallest active distance to any ribbon (considered as a straight line of no thickness) |
(not normally written out, but the tool exists)
| TkrNumHits | total number of TKR clusters |
| TkrMaxControllerHits | NOT FILLED |
| Tkr1stLayer | First layer containing a cluster (Spelling may change to TkrFirstLayer) |
| TkrNumLayersHit | total number of hit layers |
| TkrHitsInLyr00 | number of clusters in (bi)layer 0 (recon layer; 0 is at the top!) |
| TkrHitsInLyr01 | ditto layer 1 |
| TkrHitsInLyr02 | ditto layer 2 |
| TkrHitsInLyr03 | ditto layer 3 |
| TkrHitsInLyr04 | ditto layer 4 |
| TkrHitsInLyr05 | ditto layer 5 |
| TkrHitsInLyr06 | ditto layer 6 |
| TkrHitsInLyr07 | ditto layer 7 |
| TkrHitsInLyr08 | ditto layer 8 |
| TkrHitsInLyr09 | ditto layer 9 |
| TkrHitsInLyr10 | ditto layer 10 |
| TkrHitsInLyr11 | ditto layer 11 |
| TkrHitsInLyr12 | ditto layer 12 |
| TkrHitsInLyr13 | ditto layer 13 |
| TkrHitsInLyr14 | ditto layer 14 |
| TkrHitsInLyr15 | ditto layer 15 |
| TkrHitsInLyr16 | ditto layer 16 |
| TkrHitsInLyr17 | ditto layer 17(at the bottom, next to the CAL) |
These are calculated from combinations of the variables from different tools. "Flattened" means correct to make the quantity roughly independent of energy (to logE) and angle
| EvtEnergySumOpt | Event energy formed by adding the corrected tracker energy (TkrEnergyCorr) to the layer-by-layer corrected cal. energy CalEneSumCorr. |
| EvtEnergyTracker | Not calculated yet |
| EvtEnergyRaw | TkrEnergyCorr + CalEnergySum |
| EvtMcEnergySigma | difference between EvtEnerySumOpt and McEnergy, as a fraction of McEnergy |
| EvtCalEdgeAngle | Obsolete; replaced by CalTwrGap |
| EvtTkrEdgeAngle | Obsolete; replaced by Tkr1TwrGap |
| EvtLogESum | log10 of EvtEnergySumOpt, pegged between log10(20) and log10(50,000) |
| EvtTkr1EFrac | Tkr1ConE/EvtEnergySumOpt, roughly, fraction of energy carried by best track |
| EvtVtxKin | Bill opines that this variable is less useful than EvtVtxEAngle |
| EvtVtxEAngle | VtxAngle*EvtEnergySumOpt, (most of energy dependence removed) |
| EvtTkrComptonRatio | ratio of TkrTotalHits to twice the number of layers from the head of the best track to the bottom of the TKR |
| EvtTkrEComptonRatio | EvtTkrComptonRatio, flattened |
| EvtPSFModel | PSF expected from simple model; depends only on energy Formula in the process of being corrected! |
| EvtTkr1EChisq | Tkr1Chisq, flattened |
| EvtTkr1EFirstChisq | Tkr1FirstChisq, flattened |
| EvtTkr1EQual | Tkr1Qual, flattened |
| EvtTkr1PSFMdRat | Ratio of errors from covariance matrix to EvtPSFModel |
| EvtTkr1ECovDet | Tkr1CovDet, flattened in energy |
| EvtTkr2EChisq | Tkr2Chisq, flattened |
| EvtTkr2EFirstChisq | Tkr2FirstChisq, flattened |
| EvtTkr2EQual | Tkr2Qual, flattened |
| EvtCalETLRatio | Ratio of CalTransRms to CalLongRms, flattened |
| EvtCalEXtalRatio | CalXtalRatio, flattened |
| EvtCalEXtalTrunc | CalXtalsTrunc, flattened (Spelling may change to EvtCalXtalsTrunc, to match original CalXtalsTrunc) |
| EvtCalETrackDoca | CalTrackDoca, flattened |
| EvtCalETrackSep | CalTrackSep, flattened |
| EvtVtxEEAngle | EvtVtxEAngle, further flattened |
| EvtVtxEDoca | VtxDOCA, flattened |
| EvtVtxEHeadSep | VtxHeadSep, flattened |
Last Modified: 30 September, 2003
Leon Rochester (lsrea@slac.stanford.edu)
Bill Atwood (atwood@scipp.ucsc)