algorithms/reco/InclusiveKinematicsSigma.cc

0001 // SPDX-License-Identifier: LGPL-3.0-or-later
0002 // Copyright (C) 2022 Wouter Deconinck, Barak Schmookler
0003
0004 #include <Math/GenVector/LorentzVector.h>
0005 #include <Math/GenVector/PxPyPzE4D.h>
0006 #include <Math/Vector4Dfwd.h>
0007 #include <edm4eic/InclusiveKinematicsCollection.h>
0008 #include <edm4hep/MCParticleCollection.h>
0009 #include <edm4hep/Vector3f.h>
0010 #include <fmt/core.h>
0011 #include <cmath>
0012 #include <gsl/pointers>
0013
0014 #include "Beam.h"
0015 #include "Boost.h"
0016 #include "InclusiveKinematicsSigma.h"
0017
0018 using ROOT::Math::PxPyPzEVector;
0019
0020 namespace eicrecon {
0021
0022 void InclusiveKinematicsSigma::init() {}
0023
0024 void InclusiveKinematicsSigma::process(const InclusiveKinematicsSigma::Input& input,
0025                                        const InclusiveKinematicsSigma::Output& output) const {
0026
0027   const auto [mcparts, escat, hfs] = input;
0028   auto [kinematics]                = output;
0029
0030   // Get incoming electron beam
0031   const auto ei_coll = find_first_beam_electron(mcparts);
0032   if (ei_coll.empty()) {
0033     debug("No beam electron found");
0034     return;
0035   }
0036   const PxPyPzEVector ei(round_beam_four_momentum(ei_coll[0].getMomentum(),
0037                                                   m_particleSvc.particle(ei_coll[0].getPDG()).mass,
0038                                                   {-5.0, -10.0, -18.0}, 0.0));
0039
0040   // Get incoming hadron beam
0041   const auto pi_coll = find_first_beam_hadron(mcparts);
0042   if (pi_coll.empty()) {
0043     debug("No beam hadron found");
0044     return;
0045   }
0046   const PxPyPzEVector pi(round_beam_four_momentum(pi_coll[0].getMomentum(),
0047                                                   m_particleSvc.particle(pi_coll[0].getPDG()).mass,
0048                                                   {41.0, 100.0, 275.0}, m_crossingAngle));
0049
0050   // Get boost to colinear frame
0051   auto boost = determine_boost(ei, pi);
0052
0053   // Get electron variables
0054   if (escat->empty()) {
0055     debug("No scattered electron found");
0056     return;
0057   }
0058   auto kf = escat->at(0);
0059   PxPyPzEVector e_lab(kf.getMomentum().x, kf.getMomentum().y, kf.getMomentum().z, kf.getEnergy());
0060   PxPyPzEVector e_boosted = apply_boost(boost, e_lab);
0061   auto pt_e               = e_boosted.Pt();
0062   auto sigma_e            = e_boosted.E() - e_boosted.Pz();
0063
0064   // Get hadronic final state variables
0065   if (hfs->empty()) {
0066     debug("No hadronic final state found");
0067     return;
0068   }
0069   auto sigma_h = hfs->at(0).getSigma();
0070
0071   if (sigma_h <= 0) {
0072     debug("No scattered electron found or sigma zero or negative");
0073     return;
0074   }
0075
0076   auto sigma_tot = sigma_e + sigma_h;
0077
0078   // Calculate kinematic variables
0079   static const auto m_proton = m_particleSvc.particle(2212).mass;
0080   const auto y_sig           = sigma_h / sigma_tot;
0081   const auto Q2_sig          = (pt_e * pt_e) / (1. - y_sig);
0082   const auto x_sig           = Q2_sig / (4. * ei.energy() * pi.energy() * y_sig);
0083   const auto nu_sig          = Q2_sig / (2. * m_proton * x_sig);
0084   const auto W_sig           = sqrt(m_proton * m_proton + 2 * m_proton * nu_sig - Q2_sig);
0085   auto kin                   = kinematics->create(x_sig, Q2_sig, W_sig, y_sig, nu_sig);
0086   kin.setScat(kf);
0087
0088   debug("x,Q2,W,y,nu = {},{},{},{},{}", kin.getX(), kin.getQ2(), kin.getW(), kin.getY(),
0089         kin.getNu());
0090 }
0091
0092 } // namespace eicrecon