algorithms/reco/HadronicFinalState.cc

0001 // SPDX-License-Identifier: LGPL-3.0-or-later
0002 // Copyright (C) 2024 Tyler Kutz
0003
0004 #include <Math/GenVector/LorentzVector.h>
0005 #include <Math/GenVector/PxPyPzE4D.h>
0006 #include <Math/Vector4Dfwd.h>
0007 #include <edm4eic/HadronicFinalStateCollection.h>
0008 #include <edm4eic/MCRecoParticleAssociationCollection.h>
0009 #include <edm4eic/ReconstructedParticleCollection.h>
0010 #include <edm4hep/MCParticleCollection.h>
0011 #include <edm4hep/Vector3f.h>
0012 #include <fmt/core.h>
0013 #include <podio/ObjectID.h>
0014 #include <cmath>
0015 #include <gsl/pointers>
0016 #include <vector>
0017
0018 #include "Beam.h"
0019 #include "Boost.h"
0020 #include "HadronicFinalState.h"
0021
0022 using ROOT::Math::PxPyPzEVector;
0023
0024 namespace eicrecon {
0025
0026 void HadronicFinalState::init() {}
0027
0028 void HadronicFinalState::process(const HadronicFinalState::Input& input,
0029                                  const HadronicFinalState::Output& output) const {
0030
0031   const auto [mcparts, rcparts, rcassoc] = input;
0032   auto [hadronicfinalstate]              = output;
0033
0034   // Get incoming electron beam
0035   const auto ei_coll = find_first_beam_electron(mcparts);
0036   if (ei_coll.empty()) {
0037     debug("No beam electron found");
0038     return;
0039   }
0040   const PxPyPzEVector ei(round_beam_four_momentum(ei_coll[0].getMomentum(),
0041                                                   m_particleSvc.particle(ei_coll[0].getPDG()).mass,
0042                                                   {-5.0, -10.0, -18.0}, 0.0));
0043
0044   // Get incoming hadron beam
0045   const auto pi_coll = find_first_beam_hadron(mcparts);
0046   if (pi_coll.empty()) {
0047     debug("No beam hadron found");
0048     return;
0049   }
0050   const PxPyPzEVector pi(round_beam_four_momentum(pi_coll[0].getMomentum(),
0051                                                   m_particleSvc.particle(pi_coll[0].getPDG()).mass,
0052                                                   {41.0, 100.0, 275.0}, m_crossingAngle));
0053
0054   // Get first scattered electron
0055   const auto ef_coll = find_first_scattered_electron(mcparts);
0056   if (ef_coll.empty()) {
0057     debug("No truth scattered electron found");
0058     return;
0059   }
0060   // Associate first scattered electron with reconstructed electrons
0061   //const auto ef_assoc = std::find_if(
0062   //  rcassoc->begin(),
0063   //  rcassoc->end(),
0064   //  [&ef_coll](const auto& a){ return a.getSim().getObjectID() == ef_coll[0].getObjectID(); });
0065   auto ef_assoc = rcassoc->begin();
0066   for (; ef_assoc != rcassoc->end(); ++ef_assoc) {
0067     if (ef_assoc->getSim().getObjectID() == ef_coll[0].getObjectID()) {
0068       break;
0069     }
0070   }
0071   if (!(ef_assoc != rcassoc->end())) {
0072     debug("Truth scattered electron not in reconstructed particles");
0073     return;
0074   }
0075   const auto ef_rc{ef_assoc->getRec()};
0076   const auto ef_rc_id{ef_rc.getObjectID().index};
0077
0078   // Sums in colinear frame
0079   double pxsum = 0;
0080   double pysum = 0;
0081   double pzsum = 0;
0082   double Esum  = 0;
0083
0084   // Get boost to colinear frame
0085   auto boost = determine_boost(ei, pi);
0086
0087   auto hfs = hadronicfinalstate->create(0., 0., 0.);
0088
0089   for (const auto& p : *rcparts) {
0090     // Check if it's the scattered electron
0091     if (p.getObjectID().index != ef_rc_id) {
0092       // Lorentz vector in lab frame
0093       PxPyPzEVector hf_lab(p.getMomentum().x, p.getMomentum().y, p.getMomentum().z, p.getEnergy());
0094       // Boost to colinear frame
0095       PxPyPzEVector hf_boosted = apply_boost(boost, hf_lab);
0096
0097       pxsum += hf_boosted.Px();
0098       pysum += hf_boosted.Py();
0099       pzsum += hf_boosted.Pz();
0100       Esum += hf_boosted.E();
0101
0102       hfs.addToHadrons(p);
0103     }
0104   }
0105
0106   // Hadronic final state calculations
0107   auto sigma = Esum - pzsum;
0108   auto pT    = sqrt(pxsum * pxsum + pysum * pysum);
0109   auto gamma = acos((pT * pT - sigma * sigma) / (pT * pT + sigma * sigma));
0110
0111   hfs.setSigma(sigma);
0112   hfs.setPT(pT);
0113   hfs.setGamma(gamma);
0114
0115   // Sigma zero or negative
0116   if (sigma <= 0) {
0117     debug("Sigma zero or negative");
0118     return;
0119   }
0120
0121   debug("sigma_h, pT_h, gamma_h = {},{},{}", hfs.getSigma(), hfs.getPT(), hfs.getGamma());
0122 }
0123
0124 } // namespace eicrecon