utilsHfAlice3.h

// 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".
//
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// or submit itself to any jurisdiction.

/// \file HfHelperAlice3.h
/// \brief Class with helper functions for HF analyses
///
/// \author Vít Kučera <vit.kucera@cern.ch>, Inha University

#ifndef PWGHF_CORE_HFHELPERALICE3_H_
#define PWGHF_CORE_HFHELPERALICE3_H_

#include "PWGHF/Core/HfHelper.h"
#include "PWGHF/Utils/utilsAnalysis.h"

#include "Common/Core/RecoDecay.h"
#include "Common/Core/TrackSelectorPID.h"

#include <CommonConstants/MathConstants.h>
#include <CommonConstants/PhysicsConstants.h>

#include <Math/GenVector/Boost.h>
#include <Math/Vector4D.h> // IWYU pragma: keep (do not replace with Math/Vector4Dfwd.h)
#include <Math/Vector4Dfwd.h>

#include <array>
#include <cmath>
#include <vector>

namespace o2::analysis
{

enum CharmHadAlice3 { Lc = 1 };

} // namespace o2::analysis

class HfHelperAlice3
{
 public:
  /// Default constructor
  HfHelperAlice3() = default;

  /// Default destructor
  ~HfHelperAlice3() = default;

  /// Get candidate mass (ALICE3 HF data model)
  /// \tparam TCand candidate type
  /// \param cand candidate
  /// \return candidate mass
  template <o2::analysis::CharmHadAlice3 CharmHad, bool SwapHypo, typename TCand>
  static double getCandMass(const TCand& cand)
  {
    switch (CharmHad) {
      case o2::analysis::CharmHadAlice3::Lc:
        return SwapHypo ? HfHelper::invMassLcToPiKP(cand) : HfHelper::invMassLcToPKPi(cand);
      default:
        LOG(fatal) << "Unsupported charm hadron type";
        return -1.;
    }
  }

  /// Get candidate energy (ALICE3 HF data model)
  /// \tparam TCand candidate type
  /// \param cand candidate
  /// \return candidate energy
  template <o2::analysis::CharmHadAlice3 CharmHad, typename TCand>
  static double getCandEnergy(const TCand& cand)
  {
    switch (CharmHad) {
      case o2::analysis::CharmHadAlice3::Lc:
        return HfHelper::eLc(cand);
      default:
        LOG(fatal) << "Unsupported charm hadron type";
        return -1.;
    }
  }

  /// Get candidate rapidity (ALICE3 HF data model)
  /// \tparam TCand candidate type
  /// \param cand candidate
  /// \return candidate rapidity
  template <o2::analysis::CharmHadAlice3 CharmHad, typename TCand>
  static double getCandY(const TCand& cand)
  {
    if constexpr (requires { cand.flagMcRec(); }) {
      switch (CharmHad) {
        case o2::analysis::CharmHadAlice3::Lc:
          return HfHelper::yLc(cand);
        default:
          LOG(fatal) << "Unsupported charm hadron type";
          return -1.;
      }
    } else {
      switch (CharmHad) {
        case o2::analysis::CharmHadAlice3::Lc:
          return RecoDecay::y(cand.pVector(), o2::constants::physics::MassLambdaCPlus);
        default:
          LOG(fatal) << "Unsupported charm hadron type";
          return -1.;
      }
    }
  }
};

#endif // PWGHF_CORE_HFHELPERALICE3_H_