algorithms/reco/InclusiveKinematicsESigma.cc

0001 // SPDX-License-Identifier: LGPL-3.0-or-later
0002 // Copyright (C) 2022 Wouter Deconinck, Barak Schmookler
0003
0004 #include <edm4eic/EDM4eicVersion.h>
0005 #if EDM4EIC_VERSION_MAJOR >= 6
0006
0007 #include <Math/GenVector/LorentzVector.h>
0008 #include <Math/GenVector/PxPyPzE4D.h>
0009 #include <Math/Vector4Dfwd.h>
0010 #include <edm4eic/InclusiveKinematicsCollection.h>
0011 #include <edm4eic/ReconstructedParticleCollection.h>
0012 #include <edm4hep/MCParticleCollection.h>
0013 #include <edm4hep/Vector3f.h>
0014 #include <fmt/core.h>
0015 #include <cmath>
0016 #include <gsl/pointers>
0017
0018 #include "Beam.h"
0019 #include "Boost.h"
0020 #include "InclusiveKinematicsESigma.h"
0021
0022 using ROOT::Math::PxPyPzEVector;
0023
0024 namespace eicrecon {
0025
0026   void InclusiveKinematicsESigma::init() { }
0027
0028   void InclusiveKinematicsESigma::process(
0029       const InclusiveKinematicsESigma::Input& input,
0030       const InclusiveKinematicsESigma::Output& output) const {
0031
0032     const auto [mcparts, escat, hfs] = input;
0033     auto [kinematics] = output;
0034
0035     // Get incoming electron beam
0036     const auto ei_coll = find_first_beam_electron(mcparts);
0037     if (ei_coll.size() == 0) {
0038       debug("No beam electron found");
0039       return;
0040     }
0041     const PxPyPzEVector ei(
0042       round_beam_four_momentum(
0043         ei_coll[0].getMomentum(),
0044         m_particleSvc.particle(ei_coll[0].getPDG()).mass,
0045         {-5.0, -10.0, -18.0},
0046         0.0)
0047       );
0048
0049     // Get incoming hadron beam
0050     const auto pi_coll = find_first_beam_hadron(mcparts);
0051     if (pi_coll.size() == 0) {
0052       debug("No beam hadron found");
0053       return;
0054     }
0055     const PxPyPzEVector pi(
0056       round_beam_four_momentum(
0057         pi_coll[0].getMomentum(),
0058         m_particleSvc.particle(pi_coll[0].getPDG()).mass,
0059         {41.0, 100.0, 275.0},
0060         m_crossingAngle)
0061       );
0062
0063     // Get boost to colinear frame
0064     auto boost = determine_boost(ei, pi);
0065
0066     // Get electron variables
0067     auto kf = escat->at(0);
0068     PxPyPzEVector e_lab(kf.getMomentum().x, kf.getMomentum().y, kf.getMomentum().z, kf.getEnergy());
0069     PxPyPzEVector e_boosted = apply_boost(boost, e_lab);
0070     auto pt_e = e_boosted.Pt();
0071     auto sigma_e = e_boosted.E() - e_boosted.Pz();
0072
0073     // Get hadronic final state variables
0074     auto sigma_h = hfs->at(0).getSigma();
0075     auto ptsum = hfs->at(0).getPT();
0076     auto gamma_h = hfs->at(0).getGamma();
0077
0078     if (sigma_h <= 0) {
0079       debug("No scattered electron found or sigma zero or negative");
0080       return;
0081     }
0082
0083     auto sigma_tot = sigma_e + sigma_h;
0084
0085     // Calculate kinematic variables
0086     const auto y_e = 1. - sigma_e / (2.*ei.energy());
0087     const auto Q2_e = (pt_e*pt_e) / (1. - y_e);
0088
0089     const auto y_sig = sigma_h / sigma_tot;
0090     const auto Q2_sig = (pt_e*pt_e) / (1. - y_sig);
0091     const auto x_sig = Q2_sig / (4.*ei.energy()*pi.energy()*y_sig);
0092
0093     static const auto m_proton = m_particleSvc.particle(2212).mass;
0094     const auto Q2_esig = Q2_e;
0095     const auto x_esig = x_sig;
0096     const auto y_esig = Q2_esig / (4.*ei.energy()*pi.energy()*x_esig); //equivalent to (2*ei.energy() / sigma_tot)*y_sig
0097     const auto nu_esig = Q2_esig / (2.*m_proton*x_esig);
0098     const auto W_esig = sqrt(m_proton*m_proton + 2*m_proton*nu_esig - Q2_esig);
0099     auto kin = kinematics->create(x_esig, Q2_esig, W_esig, y_esig, nu_esig);
0100     kin.setScat(kf);
0101
0102     // Debugging output
0103     debug("x,Q2,W,y,nu = {},{},{},{},{}", kin.getX(),
0104             kin.getQ2(), kin.getW(), kin.getY(), kin.getNu());
0105   }
0106
0107 }
0108 #endif