AnalysisUtils.cxx File Reference

Collection of utility functions useful for analysis. More...

#include "Tools/AnalysisUtils.h"
#include <string>
#include <tuple>
#include "Framework/Exception/Exception.h"
#include "SimCore/Event/SimParticle.h"
#include "Math/Vector3D.h"

Go to the source code of this file.

Functions
std::tuple< int, const ldmx::SimParticle * >	analysis::getRecoil (const std::map< int, ldmx::SimParticle > &particleMap)
	Find and return the sim particle associated with the recoil electron.
std::tuple< int, const ldmx::SimParticle * >	analysis::getBremPhoton (const std::map< int, ldmx::SimParticle > &particleMap)
	Find and return the sim particle associated with the brem photon, if any.
bool	analysis::doesParticleHavePNDaughters (const ldmx::SimParticle &gamma, const std::map< int, ldmx::SimParticle > &particleMap)
	Helper function to getPNGamma.
const ldmx::SimParticle *	analysis::getPNGamma (const std::map< int, ldmx::SimParticle > &particleMap, const ldmx::SimParticle *recoil, const float &energyThreshold)
	Get a pointer to the sim particle associated with the photon that underwent a photo-nuclear reaction.

Detailed Description

Collection of utility functions useful for analysis.

Author

Omar Moreno, SLAC National Accelerator Laboratory

Definition in file AnalysisUtils.cxx.

Function Documentation

doesParticleHavePNDaughters()

bool analysis::doesParticleHavePNDaughters	(	const ldmx::SimParticle &	gamma,
		const std::map< int, ldmx::SimParticle > &	particleMap )

Helper function to getPNGamma.

Checks if a particle has daughter particles produced by the photonNuclear process type that are present in the particle map.

Definition at line 80 of file AnalysisUtils.cxx.

                                                     {
  for (auto daughter_id : gamma.getDaughters()) {
    if (particleMap.find(daughter_id) != std::end(particleMap)) {
      const auto daughter{particleMap.at(daughter_id)};
      const auto process_type{daughter.getProcessType()};
      if (process_type == ldmx::SimParticle::ProcessType::photonNuclear) {
        return true;
      }  // Was it PN?
    }  // Was it in the map?
  }
 
  return false;
}

References analysis::doesParticleHavePNDaughters(), and ldmx::SimParticle::getDaughters().

Referenced by analysis::doesParticleHavePNDaughters(), and analysis::getPNGamma().

getBremPhoton()

std::tuple< int, const ldmx::SimParticle * > analysis::getBremPhoton

(

const std::map< int, ldmx::SimParticle > &

particleMap

)

Find and return the sim particle associated with the brem photon, if any.

If multiple, will return the first brem photon in the list of sim particles.

Parameters

[in]

particleMap

map of sim particles

Returns

[out] Pointer to sim particle labeled as brem photon (nullptr if not found)

Definition at line 53 of file AnalysisUtils.cxx.

                                                     {
  int bremTrackID = -1;
  double bremEnergy = -9999.0;
  for (const auto& [trackID, particle] : particleMap) {
    // find the highest energy photon generated at the target
    if (particle.getEnergy() > bremEnergy  // if the energy is greatest yet
        && particle.getVertex()[2] > -5.0 &&
        particle.getVertex()[2] <
            5.0  // if the particle originates near the target
        && particle.getPdgID() == 22) {  // and the particle is a photon
      bremTrackID = trackID;
      bremEnergy = particle.getEnergy();
    }
  }  //
  if (bremTrackID != -1 && bremEnergy != -9999.0) {
    return {bremTrackID, &particleMap.at(bremTrackID)};
  } else {
    // if no brem photon is found
    return {1, nullptr};
  }
}

References analysis::getBremPhoton().

Referenced by analysis::getBremPhoton().

getPNGamma()

const ldmx::SimParticle * analysis::getPNGamma	(	const std::map< int, ldmx::SimParticle > &	particleMap,
		const ldmx::SimParticle *	recoil,
		const float &	energyThreshold )

Get a pointer to the sim particle associated with the photon that underwent a photo-nuclear reaction.

Returns the first particle in the map that underwent a PN interaction and has an energy above the threshold. If more than one particle satisfied this condition, this will NOT notice.

Parameters

[in]	particleMap	Map of sim particles
[in]	recoil	The recoil electron
[in]	energyThreshold	The energy that the photon energy must be greater than.

Returns

[out] Pointer to sim particle labeled as PN Gamma photon (nullptr if not found)

Definition at line 96 of file AnalysisUtils.cxx.

                                                                 {
  auto recoil_daughters{recoil->getDaughters()};
  for (auto recoil_daughter_id : recoil_daughters) {
    // Have we stored the recoil daughter?
    if (particleMap.find(recoil_daughter_id) != std::end(particleMap)) {
      auto recoil_daughter{particleMap.at(recoil_daughter_id)};
      // Is it a gamma?
      if (recoil_daughter.getPdgID() == 22) {
        // Does it have enough energy?
        if (recoil_daughter.getEnergy() >= energyThreshold) {
          // Are its daughters PN products?
          if (doesParticleHavePNDaughters(recoil_daughter, particleMap)) {
            return &particleMap.at(recoil_daughter_id);
          }
        }
      }
    }
  }
  return nullptr;
}

References analysis::doesParticleHavePNDaughters(), ldmx::SimParticle::getDaughters(), and analysis::getPNGamma().

Referenced by analysis::getPNGamma().

getRecoil()

std::tuple< int, const ldmx::SimParticle * > analysis::getRecoil

(

const std::map< int, ldmx::SimParticle > &

particleMap

)

Find and return the sim particle associated with the recoil electron.

Parameters

[in]

particleMap

map of sim particles

Returns

[out] Pointer to sim particle labeled as recoil electron (nullptr if not found)

Definition at line 28 of file AnalysisUtils.cxx.

                                                     {
  // The recoil electron is "produced" in the dark brem geneartion
  for (const auto& [trackID, particle] : particleMap) {
    if (particle.getPdgID() == 11 and
        particle.getProcessType() ==
            ldmx::SimParticle::ProcessType::eDarkBrem) {
      return {trackID, &particleMap.at(trackID)};
    }
  }
  // only get here if recoil electron was not "produced" by dark brem
  //   in this case (bkgd), we interpret the primary electron as also the recoil
  //   electron
  if (particleMap.find(1) != particleMap.end()) {
    return {1, &(particleMap.at(1))};
  } else {
    // need to account for overlay tracks, which replace track ID
    // 1 with 134217729 in the main sample and with 150994945 in the
    // pileup
    // this code right now is decidedly NOT future proof and only handles a
    // single encoding version
    return {134217729, &(particleMap.at(134217729))};
  }
}

References analysis::getRecoil().

Referenced by analysis::getRecoil().