strangeness_step0.cxx

// 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.
///
/// \brief this is a starting point for the Strangeness tutorial
/// \author Nepeivoda Roman (roman.nepeivoda@cern.ch)
/// \author Chiara De Martin (chiara.de.martin@cern.ch)

#include "PWGLF/DataModel/LFStrangenessTables.h"

#include "Common/DataModel/EventSelection.h"

#include "Framework/AnalysisTask.h"
#include "Framework/runDataProcessing.h"

using namespace o2;
using namespace o2::framework;
using namespace o2::framework::expressions;

// STEP 0
// Starting point: loop over all V0s and fill invariant mass histogram

struct strangeness_tutorial {
  // Histograms are defined with HistogramRegistry
  HistogramRegistry rEventSelection{"eventSelection", {}, OutputObjHandlingPolicy::AnalysisObject, true, true};
  HistogramRegistry rKzeroShort{"kzeroShort", {}, OutputObjHandlingPolicy::AnalysisObject, true, true};

  // Configurable for histograms
  Configurable<int> nBins{"nBins", 100, "N bins in all histos"};

  // Configurable for event selection
  Configurable<float> cutzvertex{"cutzvertex", 10.0f, "Accepted z-vertex range (cm)"};

  void init(InitContext const&)
  {
    // Axes
    AxisSpec K0ShortMassAxis = {200, 0.45f, 0.55f, "#it{M}_{inv} [GeV/#it{c}^{2}]"};
    AxisSpec vertexZAxis = {nBins, -15., 15., "vrtx_{Z} [cm]"};

    // Histograms
    // Event selection
    rEventSelection.add("hVertexZRec", "hVertexZRec", {HistType::kTH1F, {vertexZAxis}});

    // K0s reconstruction
    rKzeroShort.add("hMassK0Short", "hMassK0Short", {HistType::kTH1F, {K0ShortMassAxis}});
  }

  // Defining filters for events (event selection)
  // Processed events will be already fulfilling the event selection requirements
  Filter eventFilter = (o2::aod::evsel::sel8 == true);
  Filter posZFilter = (nabs(o2::aod::collision::posZ) < cutzvertex);

  void process(soa::Filtered<soa::Join<aod::Collisions, aod::EvSels>>::iterator const& collision,
               aod::V0Datas const& V0s)
  {
    // Fill the event counter
    rEventSelection.fill(HIST("hVertexZRec"), collision.posZ());

    for (const auto& v0 : V0s) {
      rKzeroShort.fill(HIST("hMassK0Short"), v0.mK0Short());
    }
  }
};

WorkflowSpec defineDataProcessing(ConfigContext const& cfgc)
{
  return WorkflowSpec{
    adaptAnalysisTask<strangeness_tutorial>(cfgc)};
}