WIP: Modify TupleToolL0Calo to take Neutrals

Adds some fixes to also takeup Neutrals with L0CaloTupleTool. Originally it uses a track extrapolator to match Electrons to its L0Clusters. Now in the case of a neutral (photon or pi0) it will access the CaloHypo position and match it to the nearest L0Calo candidate.

Phys/DecayTreeTupleTrigger/src/TupleToolL0Calo.cpp

@@ -106,8 +106,8 @@ StatusCode TupleToolL0Calo::fill( const LHCb::Particle* /* mother */, const LHCb
 
   bool test = true;
   if ( !( P->isBasicParticle() ) ) return StatusCode( test );
-
-  const std::string prefix = fullName( head );
+  bool              isneutral = ( P->particleID().pid() == 22 || P->particleID().pid() == 111 );
+  const std::string prefix    = fullName( head );
 
   double trackET, xProjection, yProjection;
 
@@ -129,8 +129,24 @@ StatusCode TupleToolL0Calo::fill( const LHCb::Particle* /* mother */, const LHCb
   yProjection = m_part2calo->caloState().y();
 
   double triggerET( -1. ), triggerHCALET( -1. ), xtrigger( 0. ), ytrigger( 0. );
-
-  if ( m_fillTriggerEt ) { triggerET = getAssociatedCluster( triggerHCALET, xtrigger, ytrigger ); }
+  if ( isneutral ) {
+    const LHCb::ProtoParticle* proto = P->proto();
+    auto                       hypos = proto->calo();
+    if ( hypos.size() > 0 && proto != NULL ) {
+      auto x = hypos[0]->position()->x();
+      auto y = hypos[0]->position()->y();
+      auto z = hypos[0]->position()->z();
+      auto E = hypos[0]->e();
+      // Calculate a few observables
+      trackET = TMath::Sqrt( TMath::Power( x, 2 ) + TMath::Power( y, 2 ) ) /
+                TMath::Sqrt( TMath::Power( x, 2 ) + TMath::Power( y, 2 ) + TMath::Power( z, 2 ) ) * E;
+      xProjection = x;
+      yProjection = y;
+      if ( m_fillTriggerEt ) { triggerET = getAssociatedCluster( x, y, xtrigger, ytrigger ); }
+    }
+  } else {
+    if ( m_fillTriggerEt ) { triggerET = getAssociatedCluster( triggerHCALET, xtrigger, ytrigger ); }
+  };
 
   // Fill the tuple
   if ( m_calo == "HCAL" ) {
@@ -285,3 +301,36 @@ double TupleToolL0Calo::getAssociatedCluster( double& hcal_energy, double& xTrig
 
   return result;
 }
+
+double TupleToolL0Calo::getAssociatedCluster( double xCell, double yCell, double& xTrigger, double& yTrigger ) {
+
+  // loop over the L0 candidates
+  LHCb::L0CaloCandidates* candidates = getIfExists<LHCb::L0CaloCandidates>( m_location );
+
+  LHCb::L0CaloCandidates::iterator cand;
+  double                           result = -1.;
+
+  double       higherPT     = -1;
+  double       minDistance2 = 999999;
+  const double distOffset   = 200;
+  for ( cand = candidates->begin(); candidates->end() != cand; ++cand ) {
+    LHCb::L0CaloCandidate* theCand = ( *cand );
+    if ( ( theCand->type() == L0DUBase::CaloType::Photon ) || ( theCand->type() == L0DUBase::CaloType::Electron ) ) {
+      double xtrig     = theCand->position().x();
+      double ytrig     = theCand->position().y();
+      double distance2 = ( xCell - xtrig ) * ( xCell - xtrig ) + ( yCell - ytrig ) * ( yCell - ytrig );
+
+      bool condition =
+          ( distance2 < distOffset * distOffset && distance2 < minDistance2 && ( theCand->et() > higherPT ) );
+      if ( condition ) {
+        xTrigger     = xtrig;
+        yTrigger     = ytrig;
+        result       = theCand->et();
+        higherPT     = result;
+        minDistance2 = distance2;
+      }
+    }
+  }
+
+  return result;
+}