Add cxx

Author: njacazio

ALICE3/Core/CMakeLists.txt

@@ -11,6 +11,7 @@
 
 o2physics_add_library(ALICE3Core
                       SOURCES TOFResoALICE3.cxx
+                              TrackUtilities.cxx
                               DelphesO2TrackSmearer.cxx
                       PUBLIC_LINK_LIBRARIES O2::Framework
                                             O2Physics::AnalysisCore)

ALICE3/Core/TrackUtilities.cxx

@@ -0,0 +1,41 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+///
+/// \file TrackUtilities.cxx
+///
+/// \brief Set of utilities for the ALICE3 track handling
+///
+/// \since  May 21, 2025
+///
+
+#include "TrackUtilities.h"
+
+#include <vector>
+
+void o2::upgrade::convertTLorentzVectorToO2Track(const int charge,
+                                                 const TLorentzVector particle,
+                                                 const std::vector<double> productionVertex,
+                                                 o2::track::TrackParCov& o2track)
+{
+  std::array<float, 5> params;
+  std::array<float, 15> covm = {0.};
+  float s, c, x;
+  o2::math_utils::sincos(static_cast<float>(particle.Phi()), s, c);
+  o2::math_utils::rotateZInv(static_cast<float>(productionVertex[0]), static_cast<float>(productionVertex[1]), x, params[0], s, c);
+  params[1] = static_cast<float>(productionVertex[2]);
+  params[2] = 0.; // since alpha = phi
+  const auto theta = 2. * std::atan(std::exp(-particle.PseudoRapidity()));
+  params[3] = 1. / std::tan(theta);
+  params[4] = charge / particle.Pt();
+
+  // Initialize TrackParCov in-place
+  new (&o2track)(o2::track::TrackParCov)(x, particle.Phi(), params, covm);
+}