Author

Nikos.nosp@m..Kon.nosp@m.stant.nosp@m.inid.nosp@m.is@ce.nosp@m.rn.c.nosp@m.h Erkca.nosp@m.n.Oz.nosp@m.can@c.nosp@m.ern..nosp@m.ch

Introduction

This package contains the AlgTool IDScanZfinder that determines the z-position of the primary pp interaction before any track reconstruction. Full details about the algorithm used can be found in:

https://twiki.cern.ch/twiki/bin/view/AtlasComputing/IDScanHowTo

Some details of the parameters and how they are set can be found in:

http://indico.cern.ch/getFile.py/access?contribId=1&resId=0&materialId=slides&confId=57832

IDScanZfinder properties:

• PhiBinSize : phi size of histogram bins ( default 0.2 degrees );
• UseOnlyPixels : if true, only use the pixel SPs ( default false );
• ROIphiWidth : phi size of RoI (must be the same as set in IDScanMain) ( default 0.2 radians );
• MinZBinSize : the size of bins in the z-histogram is MinZBinSize + RoI_eta*ZBinSizeEtaCoeff ( default 0.2mm );
• MaxZ : determines the limits of the z-histogram - reconstructed z can be up to +/- MaxZ ( default 200mm );
• ZBinSizeEtaCoeff : the size of bins in the z-histogram is MinZBinSize + RoI_eta*ZBinSizeEtaCoeff ( default 0.1 );
• DPhiDEta : to take into account that in the EC, the amount of bending as measured in DeltaPhi is dependent on the eta ( default -0.02 );
• NeighborMultiplier : A multiplicative factor to apply to the computed number of neighbors considered while spacepoints are being paired, developed to account for severe beamspot displacements ( default 1.0 )
• NumberOfPeaks : No. of possible z-positions to consider in track finding. ( default 1);
• ChargeAware : in single particle RoIs, use the fact that the one track only bends to larger or smaller phi values when making hit pairs ( default false, turned true for e and mu slices by IDScan )
• ZHistoPerPhi : if true, one z-histo per phi slice ( default false )
• VrtxDistCut : minimum fractional distance between two output vertices ( default 0, set to 10% for e & mu slices by IDScan )
• nVertexSeparation : minimum number of zbins that any two output vertices should by separated by ( default 0, set to 5 for e & mu slices by IDScan )
• VrtxMixing : if any two output peaks are too close, use this value as a weight to average the two z-positions ( experimental feature, default 0 )
• PreferCentralZ : If two peaks have the same height, report the one with lowest |z| first ( default false, set true for e & mu slices by IDScan )
• TrustSPProvider : Use all the spacepoints returned by the OnlineSpacePointTool, without applying cuts based on RoI phi width ( default true )
• FullScanMode : full-scan mode ( default false, used for full-scan slices )
• TripletMode : integer to choose triplet mode; if 0 ( default ), do not use the triplets; if 1, triplet mode is only for confirmation of pairs; if 2, each triplet contributes to the zhistos ( slower, possibly more resistant to pileup )
• TripletDZ, TripletDK, TripletDP : Cuts applied in confirming/creating triplets ( default values 25., 0.005, 0.05 )