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10/12/2001: New! AtlfastProtoJets are now available in Atlfast-01-00-08 which is in release CMT-2.4.1.
A ProtoJet is a base class proposed by the Jet Reconstruction Group. It is designed to be the input to all the Jet Reconstruction algorithms. It is really a simple interface:
virtual HepLorentzVector p();
double energy()
double ex()
double ey()
double ez()
double eta()
double phi()
double theta()
AtlfastProtoJets are ProtoJets
As of Atlfast-01-00-08 (cmt 2.4.1) Athena-Atlfast produces three types of AtlfastProtoJets. All are stored using StoreGate as ObjectVector<AtlfastProtoJet>* with different keys denoting their location. Note: This may change at a later date so that they are stored by type. The Three available protojets are:
AtlfastTowerProtoJet
These are constructed from the Athena-Atlfast calorimeter "Cells". These are simple cells or more properly towers of size 0.1 by 0.1 in eta and phi respectively. Each AtlfastTowerProtoJet represents one of these cells.
AtlfastClusterProtoJet
These are constructed from Athena-Atlfast clusters. The clusters are made by Atlfast::ClusterMaker. This has a simple cone algorithm which takes cells in a cone and sums their 4-mom. The cluster maker can be configured in the StandardAtlfastOptions.txt file with the following commands
ClusterMaker.RConeBarrel
ClusterMaker.RConeForward
ClusterMaker.minInitiatorET
ClusterMaker.minClusterET
AtlfastFinalStateProtoJet
These are constructed from all final state particles.
All AtlfastProtoJets are constructed by AtlfastProtoJetMaker. In addition, AtlfastProtoJetMaker also constructs a JetRec Jet for each ProtoJet it makes. The Jet in this case is a trivial jet containing just the ProtoJet.
To include this in your Athena-Atlfast job put the following line in the AtlfastStandardOptions.txt file after the line
#include "AtlfastDoNotTouch.txt"
Atlfast.members +={"Atlfast::AtlfastProtoJetMaker/AtlfastProtoJetMaker"};
This algorithm has a number of steering parameters that can be set in the StandardAtlfastOptions.txt. Firstly there is the Construct variables. These tell the algorithm whether to make each of the AtlfastProtoJet types, the default for all is true, but any can be set to false:
AtlfastProtoJetMaker.TowerPJConstruct = false;
AtlfastProtoJetMaker.ClusterPJConstruct = false;
AtlfastProtoJetMaker.FinalStatePJConstruct = false;
The output key used by StoreGate for each of these can also be set. Below is shown the default values:
AtlfastProtoJetMaker.OutputTowerPJKey = "/Event/AtlfastTowerProtoJets";
AtlfastProtoJetMaker.OutputClusterPJKey = "/Event/AtlfastClusterProtoJets";
AtlfastProtoJetMaker.OutputFinalStatePJKey = "/Event/AtlfastFinalStateProtoJets";
The output Keys for the JetRec Jets can also be set:
AtlfastProtoJetMaker.OutputTowerJetKey = "/Event/AtlfastTowerJets";
AtlfastProtoJetMaker.OutputClusterJetKey = "/Event/AtlfastClusterJets";
AtlfastProtoJetMaker.OutputFinalStateJetKey = "/Event/AtlfastFinalStateJets";
Finally you can switch on smearing for the Cluster and Tower ProtoJets. A very naive smearing algorithm inherited from the AtlfastFortran is implemented here to smear the ProtoJets. The default for smearing is false. This smearing has not been fully tested and should not at the moment be used for serious physics study. A correct smearer is being worked at the moment and should be available soon.
AtlfastProtoJetMaker.TowerPJSmearOn = false;
AtlfastProtoJetMaker.ClusterPJSmearOn = false;