Mattione GlueX Analysis Factories
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Contents
Summary
- In his/her plugin, a user specifies the reactions he/she wants to study (DReaction objects), then just asks JANA for the results (DTrackCombo objects).
- Creates all possible track combinations for the desired reaction; user then cuts on the likelihood that those combinations represent the hypothesized reaction.
User Plugin DReaction Factory
- DReaction.h located in DANA libraries, DReaction_factory.h located in user plugin (along with a factory generator for it).
- Below shows how to set up DReaction for a Y(2175) analysis.
//------------------
// init
//------------------
jerror_t DReaction_factory::init(void)
{
// Setting the PERSISTANT prevents JANA from deleting
// the objects every event so we only create them once.
SetFactoryFlag(PERSISTANT);
DReaction* locReaction;
DReactionStep* locReactionStep;
// Make as many DReaction objects as desired
locReaction = new DReaction();
locReaction->Set_ReactionName("Y2175");
//g, p -> phi(2175), (p) locReactionStep = new DReactionStep(); locReactionStep->Set_InitialParticleID(Gamma); locReactionStep->Set_TargetParticleID(Proton); locReactionStep->Add_FinalParticleID(Unknown); //phi(2175) locReactionStep->Add_FinalParticleID(Proton); locReactionStep->Set_MissingParticleIndex(1); //proton missing locReaction->Add_ReactionStep(locReactionStep); dReactionStepPool.push_back(locReactionStep); //prevent memory leak //phi(2175) -> pi+, pi-, phi locReactionStep = new DReactionStep(); locReactionStep->Set_InitialParticleID(Unknown); //phi(2175) locReactionStep->Set_TargetParticleID(Unknown); //no target for this step locReactionStep->Add_FinalParticleID(PiPlus); locReactionStep->Add_FinalParticleID(PiMinus); locReactionStep->Add_FinalParticleID(phiMeson); locReactionStep->Set_MissingParticleIndex(-1); //none missing locReaction->Add_ReactionStep(locReactionStep); dReactionStepPool.push_back(locReactionStep); //prevent memory leak //phi -> K+, K- locReactionStep = new DReactionStep(); locReactionStep->Set_InitialParticleID(Unknown); //phi(2175) locReactionStep->Set_TargetParticleID(Unknown); //no target for this step locReactionStep->Add_FinalParticleID(KPlus); locReactionStep->Add_FinalParticleID(KMinus); locReactionStep->Set_MissingParticleIndex(-1); //none missing locReaction->Add_ReactionStep(locReactionStep); dReactionStepPool.push_back(locReactionStep); //prevent memory leak _data.push_back(locReaction); return NOERROR; }
DTrackCombo Factory
- (Would be) Located in DANA
- Still finalizing class format, but looks similar to DReaction, except with full particles instead of just PIDs.
- Generate a DTrackCombo object for each possible combination of detected tracks (DBeamPhotons ignored).
- For each q = +/-/0 particle in a given DReaction, all detected q = +/-/0 tracks are tested as to whether or not they are that particle (PID is NOT assumed).
DKinFitTrackCombo Factory
- (Would be) Located in DANA
- Still finalizing class format, but looks similar to DReaction, except with full particles instead of just PIDs.
- Generate a DKinFitTrackCombo object for each possible combination of DTrackCombos and DBeamPhotons (ignore all DBeamPhotons "too far" from RF time).
- Perform a single, full kinematic fit testing whether the DTrackCombo matches the DReaction: includes all mass, vertex, timing constraints (vertex & timing not yet implemented).
User Plugin DEventProcessor
extern "C" { void InitPlugin(JApplication *app) { InitJANAPlugin(app); app->AddProcessor(new DEventProcessor_Y2175()); app->AddFactoryGenerator(new DFactoryGenerator_DReaction()); } } // "C" jerror_t DEventProcessor_Y2175::evnt(JEventLoop *locEventLoop, int eventnumber) { vector<const DKinFitTrackCombo*> locKinFitTrackCombos; locEventLoop->Get(locKinFitTrackCombos); //DO HISTS/CUTS/TUPLES HERE return NOERROR; }
Cutting/Histogramming
- Coming Soon...
Tupling
- Haven't gotten this far yet...