xAOD::PVHelpers Namespace Reference

Functions
std::pair< float, float >	getZCommonAndError (const xAOD::EventInfo *eventInfo, const xAOD::EgammaContainer *egammas, float convPtCut=2e3)
	Return zCommon and zCommonError. More...
float	getVertexSumPt (const xAOD::Vertex *vertex, int power=1, bool useAux=true)
	Loop over track particles associated with vertex and return scalar sum of pT^power in GeV (from auxdata if available and useAux = true) More...
TLorentzVector	getVertexMomentum (const xAOD::Vertex *vertex, bool useAux=true, const std::string &derivationPrefix="")
	Return vector sum of tracks associated with vertex (from auxdata if available and useAux = true) More...
const xAOD::Vertex *	getHardestVertex (const xAOD::VertexContainer *vertices)
	Return vertex with highest sum pT^2. More...
TLorentzVector	getTrackAtFirstMeasurement (const xAOD::TrackParticle *tp)
	Return track at first measurment, useful as proxy to conversion vertex pT. More...
bool	passConvSelection (const xAOD::Photon *photon, float convPtCut=2e3)
	Check if photon is converted, and tracks have Si hits and pass selection. More...
bool	passConvSelection (const xAOD::Vertex &conversionVertex, size_t i, float convPtCut)
	Check if track i of conversion vertex pass selection (Si hits and pt) More...

Function Documentation

getHardestVertex()

const xAOD::Vertex * xAOD::PVHelpers::getHardestVertex

(

const xAOD::VertexContainer *

vertices

)

Return vertex with highest sum pT^2.

Definition at line 28 of file PhotonVertexHelpers.cxx.

{
  // Check PV collection
 
  // Check for primary vertex in collection
  for (const auto* vertex : *vertices) {
    if (vertex->vertexType() == xAOD::VxType::VertexType::PriVtx)
      return vertex;
  }
 
  return nullptr;
}

getTrackAtFirstMeasurement()

TLorentzVector xAOD::PVHelpers::getTrackAtFirstMeasurement

(

const xAOD::TrackParticle *

tp

)

Return track at first measurment, useful as proxy to conversion vertex pT.

Definition at line 149 of file PhotonVertexHelpers.cxx.

{
 
  static const SG::AuxElement::ConstAccessor<std::vector<float>> accParameterPX(
    "parameterPX");
  static const SG::AuxElement::ConstAccessor<std::vector<float>> accParameterPY(
    "parameterPY");
 
  TLorentzVector v;
  v.SetPtEtaPhiM(tp->pt(), tp->eta(), tp->phi(), 0.);
  if (!accParameterPX.isAvailable(*tp) || !accParameterPY.isAvailable(*tp)) {
    return v;
  }
 
  for (unsigned int i = 0; i < accParameterPX(*tp).size(); ++i) {
    if (tp->parameterPosition(i) == xAOD::FirstMeasurement) {
      v.SetPxPyPzE(accParameterPX(*tp)[i], accParameterPY(*tp)[i], 0, 0);
      return v;
    }
  }
  return v;
}

getVertexMomentum()

TLorentzVector xAOD::PVHelpers::getVertexMomentum	(	const xAOD::Vertex *	vertex,
		bool	useAux = true,
		const std::string &	derivationPrefix = ""
	)

Return vector sum of tracks associated with vertex (from auxdata if available and useAux = true)

Definition at line 174 of file PhotonVertexHelpers.cxx.

{
  TLorentzVector v;
 
  SG::AuxElement::ConstAccessor<float> pt(derivationPrefix + "pt");
  SG::AuxElement::ConstAccessor<float> eta(derivationPrefix + "eta");
  SG::AuxElement::ConstAccessor<float> phi(derivationPrefix + "phi");
 
  if (useAux and pt.isAvailable(*vertex) and eta.isAvailable(*vertex) and phi.isAvailable(*vertex)) {
    // protect against decoreated nan values (from Rel24 on?)
    if(!std::isnan(pt(*vertex)) and !std::isnan(eta(*vertex)) and !std::isnan(phi(*vertex))){
      v.SetPtEtaPhiM(pt(*vertex), eta(*vertex), phi(*vertex), 0.0);
      return v;
    }
    else{
      using namespace asg::msgUserCode;
      ANA_MSG_WARNING("PhotonVertexHelpers::getVertexMomentum : "
                      << "NaN detected in Vertex decorations (pt, eta, phi) = "
                      << " (" <<  pt(*vertex) <<  ", " << eta(*vertex) << ", " << phi(*vertex) << ")");
      ANA_MSG_WARNING("PhotonVertexHelpers::getVertexMomentum : "
                      << "Recompute sum tracks 4-momenta from associated TrackParticles");
    }
  }
 
  // Sum the 4-momenta of all track particles at the vertex
  const xAOD::TrackParticle* tp = nullptr;
  for (size_t i = 0; i < vertex->nTrackParticles(); ++i) {
    tp = vertex->trackParticle(i);
    if (tp == nullptr) {
      continue; // protect against thinned tracks
    }
    v += tp->p4();
  }
  return v;
}

getVertexSumPt()

float xAOD::PVHelpers::getVertexSumPt	(	const xAOD::Vertex *	vertex,
		int	power = 1,
		bool	useAux = true
	)

Loop over track particles associated with vertex and return scalar sum of pT^power in GeV (from auxdata if available and useAux = true)

Definition at line 214 of file PhotonVertexHelpers.cxx.

{
 
  std::string pw = (power == 1) ? "sumPt" : Form("sumPt%d", power);
  SG::ConstAccessor<float> acc(pw);
  if (useAux and acc.isAvailable(*vertex))
    return acc(*vertex);
 
  // Loop over all track particles, sum up their pt
  float pt = 0.0;
  const xAOD::TrackParticle* tp = nullptr;
  for (size_t i = 0; i < vertex->nTrackParticles(); ++i) {
    tp = vertex->trackParticle(i);
    if (tp == nullptr)
      continue; // protect against slimmed tracks
 
    pt += pow(tp->pt() / 1e3, power);
  }
  return pt;
}

getZCommonAndError()

std::pair< float, float > xAOD::PVHelpers::getZCommonAndError	(	const xAOD::EventInfo *	eventInfo,
		const xAOD::EgammaContainer *	egammas,
		float	convPtCut = 2e3
	)

Return zCommon and zCommonError.

Definition at line 43 of file PhotonVertexHelpers.cxx.

{
  // Static accessors
  static const SG::AuxElement::Accessor<float> zvertex("zvertex");
  static const SG::AuxElement::Accessor<float> errz("errz");
  static const SG::AuxElement::Accessor<float> HPV_zvertex("HPV_zvertex");
  static const SG::AuxElement::Accessor<float> HPV_errz("HPV_errz");
 
  // Clear values
  float zCommon = 0.0, zCommonError = 0.0;
 
  // Beam position is the base for zCommon weighted average
  double beamPosZ = eventInfo->beamPosZ();
  double beamPosSigmaZ = eventInfo->beamPosSigmaZ();
 
  if( beamPosSigmaZ == 0 )
    beamPosSigmaZ = 10;
 
  zCommon = beamPosZ / beamPosSigmaZ / beamPosSigmaZ;
  zCommonError = 1.0 / beamPosSigmaZ / beamPosSigmaZ;
 
  // Include z-position pointed at by egammas
  for (const xAOD::Egamma* egamma : *egammas) {
    if (egamma == nullptr) {
      continue;
    }
 
    const xAOD::Photon* photon = nullptr;
    if (egamma->type() == xAOD::Type::Photon)
      photon = dynamic_cast<const xAOD::Photon*>(egamma);
 
    if (photon && passConvSelection(photon, convPtCut)) {
      if (!HPV_zvertex.isAvailable(*photon) || !HPV_errz.isAvailable(*photon)) {
        continue;
      }
      if (HPV_errz(*photon) == 0.0) {
        continue;
      }
      zCommon += HPV_zvertex(*photon) / HPV_errz(*photon) / HPV_errz(*photon);
      zCommonError += 1.0 / HPV_errz(*photon) / HPV_errz(*photon);
    } else {
      if (!zvertex.isAvailable(*egamma) || !errz.isAvailable(*egamma)) {
        continue;
      }
      if (errz(*egamma) == 0.0) {
        continue;
      }
      zCommon += zvertex(*egamma) / errz(*egamma) / errz(*egamma);
      zCommonError += 1.0 / errz(*egamma) / errz(*egamma);
    }
  }
 
  // Normalize by error (weighted average)
  {
    // Tell clang to optimize assuming that FP exceptions can trap.
    // Otherwise, it can vectorize these divisions, which can lead to
    // spurious division-by-zero traps from unused vector lanes.
    CXXUTILS_TRAPPING_FP;
    zCommon /= zCommonError;
    zCommonError = 1.0 / sqrt(zCommonError);
  }
 
  return std::make_pair(zCommon, zCommonError);
}

passConvSelection() [1/2]

bool xAOD::PVHelpers::passConvSelection	(	const xAOD::Photon *	photon,
		float	convPtCut = 2e3
	)

Check if photon is converted, and tracks have Si hits and pass selection.

Definition at line 132 of file PhotonVertexHelpers.cxx.

{
  const xAOD::Vertex* conversionVertex = photon->vertex();
  if (conversionVertex == nullptr)
    return false;
 
  size_t NumberOfTracks = conversionVertex->nTrackParticles();
  for (size_t i = 0; i < NumberOfTracks; ++i) {
    if (passConvSelection(*conversionVertex, i, convPtCut))
      return true;
  }
 
  return false;
}

passConvSelection() [2/2]

bool xAOD::PVHelpers::passConvSelection	(	const xAOD::Vertex &	conversionVertex,
		size_t	i,
		float	convPtCut
	)

Check if track i of conversion vertex pass selection (Si hits and pt)

Definition at line 112 of file PhotonVertexHelpers.cxx.

{
  const xAOD::TrackParticle* tp = conversionVertex.trackParticle(i);
 
  if (!xAOD::EgammaHelpers::numberOfSiHits(tp))
    return false;
  // pt1,pt2 is only set for 2-track vertices
  if (conversionVertex.nTrackParticles() == 1)
    return xAOD::EgammaHelpers::momentumAtVertex(conversionVertex).perp() >
           convPtCut;
 
  std::string s = Form("pt%lu", i + 1);
  SG::ConstAccessor<float> acc (s);
  return (acc.withDefault(conversionVertex, 0) > convPtCut);
}