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This page contains tables documenting many of the detector-level variables available for BtaCandidates in the Event Store.

Contents:

• Includes and Pointers Needed (pointer names used throughout this page)
• Track Fit Information
• Particle Identification (PID) Quality
• Particle Identification (PID) Information
• Calorimeter Information
• Muon System Information
• Other common quantities

Needed Includes and Pointers

#include "BetaMicroAdapter/BtaMicroAdapter.hh"
#include "BetaMicroAdapter/BtaCalQual.hh"
#include "BetaMicroAdapter/BtaPidQual.hh"
#include "BetaMicroAdapter/BtaTrkQual.hh"
#include "BetaMicroAdapter/BtaPidInfo.hh"
#include "BetaMicroAdapter/BtaIfrQual.hh"

BtaCandidate* MyBtaCand;
const BtaTrkQual* TrkQual = MyBtaCand->getMicroAdapter()->getTrkQual();
const BtaCalQual* CalQual = MyBtaCand->getMicroAdapter()->getCalQual();
const BtaPidQual* PidQual = MyBtaCand->getMicroAdapter()->getPidQual();
const BtaPidInfo* PidInfo = MyBtaCand->getMicroAdapter()->getPidInfo();
const BtaIfrQual* IfrQual = MyBtaCand->getMicroAdapter()->getIfrQual();

.

Tracking Information
Variable	Type	Range	Packing	Size in DB	Description
TrkQual->nDof()	Int	0->255	Integer	1 byte	number of degrees of freedom of the track-fit
TrkQual->prob()	Float	0->1	N/A	N/A	Probability of the chi-squared of the track fit.  Not stored directly in the database - calculated from other, stored quantities.
TrkQual->chi2()	Float	0->1000	Logarithmic	2 bytes	Chi-squared of the track fit
TrkQual->trackLength()	Float	0->100	Logarithmic	1 byte	Track length (cm) from the first to the last hit
TrkQual->startFoundRange()	Float	0->100	Logarithmic	1 byte	Track length (cm) from origin to the first hit
TrkQual->nSvtHits()	Int	0->15	Integer	4 bits	The number of z and phi hits in the SVT that are on this candidate's track. Each of the SVT's 5 layers provides both z and phi information. It is possible to have more than 10 hits (5 phi + 5z) due to low transverse-momentum charged tracks which can curl up in the detector. FYI, a track with Pt=0.1 GeV will make it to the outer edge of the SVT-DCH interface.
TrkQual->SvtPattern()	Int	0->1023	Integer	10 bits	The 10 bits of the word correspond to whether one of the 10 views of the SVT registered a hit for this candidate: Layer 5 z-view = Most Significant Bit Layer 4 z-view Layer 3 z-view Layer 2 z-view Layer 1 z-view Layer 5 r/phi-view Layer 4 r/phi-view Layer 3 r/phi-view Layer 2 r/phi-view Layer 1 r-phi-view = Least Significant Bit
TrkQual->SvtOn(int layer)	Bool	True/False	Integer	1 bit each for 10 layers	True if this candidate has a SVT hit on track for the given layer.  Each of the 5 SVT layers contains both r and phi info: Layers 0->4 represent r-phi hits on the 5 layers, with 0 denoting the innermost layer. Layers 5->9 represent z hits on the 5 layers, with 5 denoting the innermost layer.
TrkQual->firstDchHit()	Int	0->255	Integer	1 byte	Innermost layer of the DCH registering a hit associated with this charged candidate's track. There are 40 layers in the Drift Chamber.
TrkQual->lastDchHit()	Int	0->255	Integer	1 byte	Outermost layer of the DCH registering a hit associated with this candidate's track. There are 40 layers in the Drift Chamber.
TrkQual->nDchHits()	Int	0->255	Integer	1 byte	Number of DCH layers registering hits associated with this candidate's track. There are 40 layers in the Drift Chamber. Due to low transverse-momentum tracks which can curl up in the detector, this number can be greater than 40.
TrkQual->pidHypo()	Int	0->7	Integer	3 bits	Particle Hypothesis used while fitting the track (i.e. what mass was used). The mapping is as follows: 0= electron 1= muon 2= pion 3= kaon 4= proton
TrkQual->fitStatus()	Bool	True/False	Integer	1 bit	Status of the Track Fit
Particle Identification Quality
Variable	Type	Range	Packing	Size in DB	Description
PidQual->dEdXSvt()	Float	0->100	Logarithmic	1 byte	dE/dx (arbitrary units) determined from the SVT hits
PidQual->nSamplesDeDxSvt()	Int	0->255	Integer	1 byte	# of samples in the SVT used to calculate dEdXSvt()
PidQual->dEdXDch()	Float	0->1000	Logarithmic	1 byte	dE/dX (arbitrary units) for determined from the Dch hits
PidQual->nSamplesDeDxDch()	Int	0->255	Integer	1 byte	# of samples in the DCH used to calculate dEdXDch()
PidQual->deltaDchMomentum()	Float	-100->0 MeV	Logarithmic	1 byte	Candidate's momentum at the entrance of the Drift Chamber minus the momentum at the origin.
PidQual->deltaDrcMomentum()	Float	-100->0 MeV	Logarithmic	1 byte	Candidate's momentum at the entrance of the DIRC minus the momentum at the origin.
PidQual->drcInBar()	Int	0-143	Integer	1 byte	ID of the bar the candidate enters first. 0 marks the bar at the top center of the detector. The rest of the bars are numbered in ascending order, following positive right-handed rotation around the electron beam. Note that the number 0 is also stored when the track does not go into the DIRC fiducial volume. Watch for confusion with the actual bar 0!
PidQual->drcExitBar()	Int	0-3	Integer	2 bits	ID number of the bar the candidate exits the DIRC from, relative to the bar the candidate first enters. 0: Exit Bar= Entry Bar 1: Exit Bar= Entry Bar + 1 2: Exit Bar= Entry Bar - 1 3: Greater than 1 bar of displacement
PidQual->drcXPos()	Double	-2 -> +2 cm	Integer	6 bits	x position where the candidate first enters the "inBar," relative to the center of the bar. (half-width of bar is actually 1.85 cm)
PidQual->thetaC()	Float	0->1  radian	Flat	2 bytes	The opening angle of the Cerenkov ring emitted by the charged candidate.
PidQual->thetaCErr()	Float	0->1 radian	Logarithmic	2 bytes	Error on the opening angle of the Cerenkov ring.
PidQual->ringNPhot()	Int	0->255	Integer	1 byte	Measured number of signal photons in the Cerenkov ring fit to the detected photons of this charged candidate.
PidQual->ringNBkgd()	Int	0->255	Integer	1 byte	Measured number of background photons in the Cerenkov ring fit to the detected photons of this charged candidate.
PidQual->ringNExPhot(const PdtEntry* p)	Int	0->255	Integer	1 byte each for the 5 hypothesis (5 bytes total)	Number of photons expected to be associated with a ring of this particle's momentum, given Particle ID Entry p.
PidQual->phiAtEMC()	Float				phi of intercept of the track with the EMC
PidQual->thetaAtEMC()	Float				theta of intercept of the track with the EMC
Particle Identification Information
Variable	Type	Range	Packing	Size in DB	Description
PidInfo->charge()	Int	-1->+1	Integer	1 byte	Charge of this candidate
PidInfo->consistency(const PdtEntry* p, detectors det)	Consistency	0->1	Logarithmic	1 byte each for 5 detectors and 5 hypothesis (25 bytes total)	Gives the consistency of a single detector's ( PidSystem::ifr,PidSystem::emc,PidSystem::drc,PidSystem::dch, PidSystem::svt) information with a given particle hypothesis, p.
Calormetric Information
Variable	Type	Range	Packing	Size in DB	Description
CalQual->lateralMoment()	Float	0->1	Logarithmic	1 byte	The lateral moment of the cluster associated with this track. Ratio of 1) to 2): 1) sum of energies of all but the 2 most energetic crystals, weighted by the square of distance to the cluster center 2) Sum of 1) and the energies of the 2 most energetic cystals, which are weighted by r^2. r is the length scale of a crystal, 5 cm.
CalQual->absZernike42()	Float	0->1	Logarithmic	1 byte	the absolute value of the complex Zernike(4,2) moment.
CalQual->absZernike20()	Float	0->1	Logarithmic	1 byte	the absolute value of the complex Zernike(2,0) moment.
CalQual->s1s9()	Float	0->1	Logarithmic	1 byte	For a cluster, the ratio of the sums of the energies of the central crystal to the central 9 crystals surrounding the centroid.
CalQual->s9s25()	Float	0->1	Logarithmic	1 byte	For a cluster, the ratio of the sums of the energies of the central 9 crystals to the central 25 crystals surrounding the centroid.
CalQual->secondMomentTP()	Float	0->1	Logarithmic	1 byte	The second moment, in theta-phi, of the cluster.
CalQual->rawEnergy()	Float	0->50	Logarithmic	2 bytes	Raw energy measured in EMC (GeV), after digi calibration is applied, but with NO leakage corrections.
CalQual->ecalEnergy()	Float	0->50	Logarithmic	2 bytes	energy measured in EMC (GeV), after digi calibration and leakage corrections are applied!
CalQual->trkEmcMatchConsistency()	Consistency	0->1	Logarithmic	1 byte	The consistency of the match between the charged track and the EMC bump, assuming the (conservative) pion hypothesis.
CalQual->nBumps()	Int	0->15	Integer	4 bits	The number of bumps in the calorimeter associated with this candidate.
CalQual->nCrystals()	Float				The number of "hit" crystals for this bump. For a crystal shared between bumps, a splitting algorithm is applied to determine how much of its energy is given to each bump. Thus, it is a float type.
CalQual->centroid()	HepPoint	0->500 cm	Logarithmic	2 bytes each for 3 directions (6 bytes total)	Centroid of the cluster/bump
CalQual->covMat()	HepSymMatrix		Logarithmic	2 bytes each for 4 entries (8 bytes total)	4x4 covariance matrix (E,theta,phi,r)
CalQual->neutPid()	Int	0->4	Integer	4 bits	PID type with which the EMC and IFR quantities have been computed (none = -1,gamma = 0,pi0= 1,K0L= 2, neutron = 3, anti_neutron = 4)
CalQual->isOk()	Bool	True/False			returns true if the CalorObject (Cluster or Bump) has no dead or noisy Crystals in it. Also the Object is not in a ROM which is suffering from online dataflow damage or a noisy power supply.
CalQual->isNoisy()	Bool	True/False			true if at least one crystal in the CalorObject is noisy.
CalQual->isNearDead()	Bool	True/False			true if at least one crystal in the CalorObject is dead.
CalQual->isDamaged()	Bool	True/False			true if at least one crystal in the CalorObject is in a Read-Out Module that has online dataflow damage in that event.
CalQual->isFlickery()	Bool	True/False			true if at least one crystal in the CalorObject is in a Read-Out Module that has power supply noise (flicker). This is worked out by measuring the occupancy of the Read-Out Module in the event, and determining if it is over the following cuts: Read-Out Module occupancy of digis with energy greater than 1MeV has to be greater than or equal to 50% (barrel) and 100% (end cap) (energetic bhabha's can cause all the crystals in an endcap Read-Out Module to be on)
CalQual->maxIsNoisy()	Bool	True/False			true if any of the central 9 crystals of the CalorObject (where center = highest energy crystal) is noisy.
CalQual->maxIsNearDead()	Bool	True/False			true if any of the central 9 crystals of the CalorObject is dead.
CalQual->maxIsDamaged()	Bool	True/False			true if any of the central 9 crystals of the CalorObject is in a online dataflow damaged Read-Out Module.
CalQual->maxIsFlickery()	Bool	True/False			true if any of the central 9 crystals of the CalorObject is in a flickery (flickery defined in description of the isFlickery method, above) the Read-Out Module.
Muon System Information
Variable	Type	Range	Packing	Size in DB	Description
IfrQual->IfrNStrips()	Int	0->255	Integer	1 byte	Number of "hit" strips associated with this candidate.
IfrQual->nStrips(int layer)	Int	0->14	Integer	4 bits each for 21 layers and 4 bits for the barrell/endcap division (22x4 bits = 11 bytes)	The number of strips hit in a given IFR layer. Only the range 0->14 is physical.  The one layer which returns 15 is a dummy (not physical) layer used to denote the barrel-endcap interface. Lower numbered layers are in the barrel, while higher numbered layers are in the encap. The total number of strips in both cylindrical RPC layers is stored in layer=0.
IfrQual->IfrLayHits()	Int	0->20	* see below	* see below	Number of "hit" layers in the IFR associated with this candidate. If there are hits in both layers of the cylindrical RPC it is counted as one layer in this total.
IfrQual->firstHit()	Int	-1->20	* see below	* see below	Number of the innermost IFR layer with a hit associated with this candidate. (-1 = cylindrical layer)
IfrQual->lastHit()	Int	-1->20	* see below	* see below	Number of the outermost IFR layer with a hit associated with this candidate. (-1 = cylindrical layer)
IfrQual->hasInner()	Bool	True/False	* see below	* see below	True when candidate has a hit in the "inner" 2-layer cylindrical layers.
IfrQual->hasBarrel()	Bool	True/False	* see below	* see below	True when candidate has a hit in the "outer" 19-layer barrel region of IFR
IfrQual->lastBarrel()	Int	0->20	* see below	* see below	The number of the last barrel layer hit in the IFR.
IfrQual->hasFWD()	Bool	True/False	* see below	* see below	True when candidate has a hit in the 18-layer forward encap of IFR
IfrQual->hasBWD()	Bool	True/False	* see below	* see below	True when candidate has a hit in the 18-layer backward encap of IFR
IfrQual->expectedInteractionLengths()	Float	0->10	Logarithmic	1 byte	The swimmer calculates the number of interaction lengths to the last active RPC chamber along the trajectory of the track. This is a calculation independent of the chambers actually hit.
IfrQual->measuredInteractionLengths()	Float	0->10	Logarithmic	1 byte	Number of interactions lengths through which the candidate's path travels. Dominated by DRC, EMC, and IFR because of their high densisty. Caculated by a "swimmer."
IfrQual->interactionLengthsBeforeIron()	Float	0->10	Logarithmic	1 byte	Number of interactions lengths traversed by a candidate, not including the IFR iron. Again, using a "swimmer."
IfrQual->IfrTrkMatchChi2()	Float	0->50	Logarithmic	1 byte	This is the sum of the squares of the residuals (in both readout perpendicular views) of the measured hit positions w.r.t. the swum track, exrapolated from the DCH. The chi-squared is then normalized to the number of degrees of freedom.
IfrQual->IfrEmcMatch()	Float	0->1000	Logarithmic	1 byte	Numbering indicating the consistency of the IFR hits with the EMC bumps/clusters of this track..
IfrQual->clusterFitChi2()	Float				For a candidate's IFR cluster, the individual strips for each view are extracted. In each of the 2 perpendicular views, the coordinates of the strips are fit to a second order polynomial. The chi-square of these two fits are then summed to produce this number. This quantity is thus independent of tracking.
* The IfrQual quantities marked with this asterisk are not actually stored in the database. They are calculated from IfrQual->nStrips(int layer).

How to find other commonly used quantities

• To get the consistency(significance level)/likelihood that a candidate is particle XXX:

     // get a single detector consistency object
     const Consistency& c1=PidInfo->consistency(Pdt::lookup(PdtPdg::XXX),PidSystem::yyy);
     // to get significance level:
     float myConsistency1= c1.consistency();
     // to get likelihood
     float myLikelihood1= c1.likelihood();
  

  where XXX is the type of particle. For example XXX could be any of (but is not restricted to) the following: e_minus (an electron), mu_minus (a muon), pi_minus (a charged Pion), K_minus (a charged Kaon), p_plus (a proton) and where yyy is the detector. yyy could be any of the following: ifr, emc, drc, dch, svt.

• To find the candidate trajectory's point of closest approach (in an XY projection), to a particular point, (X,Y,Z):

     #include "TrkFitter/TrkPocaXY.hh"
     #include "TrkBase/TrkAbsFit.hh"
     
     TrkPocaXY pocaxy(cand->trkAbsFit()->traj(),0,HepPoint(X,Y,Z));
     HepPoint closestApproach= cand->trkAbsFit()->position(pocaxy.fltl1());
  

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