Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief anti-deuteron spectrum in upslion decays
  class ARGUS_1990_I283027 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1990_I283027);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(UnstableParticles(), "UFS");
      // histograms
      book(_h_p,1,1,1);
      book(_w_ups,"TMP/w_ups");
    }


    /// Recursively walk the decay tree to find decay products of @a p
    void findDecayProducts(Particle mother, Particles& deut) {
      // deuteron id code
      static const long id = -1000010020;
      for(const Particle & p: mother.children()) {
    if(p.pid() == id) {
      deut.push_back(p);
    }
    else if(!p.children().empty())
      findDecayProducts(p, deut);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      for(const Particle & ups : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==553) ) {
    _w_ups->fill();
    Particles deut;
    findDecayProducts(ups, deut);
    if(deut.empty()) continue;
    LorentzTransform boost;
    if (ups.p3().mod() > 1*MeV)
      boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
    for(const Particle& p : deut) {
      double mom = boost.transform(p.momentum()).p3().mod();
      _h_p->fill(mom);
    }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // direct upsilon decays, i.e. to gg gamma and ggg so need to renormalize
      // factor and values from arxiv:0612019
      double Bmumu=0.0249, rhad = 3.56;
      double fact = 1.-(3.+rhad)*Bmumu;
      scale(_h_p, 1e5/fact / *_w_ups);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_p;
    CounterPtr _w_ups;
    /// @}


  };


  RIVET_DECLARE_PLUGIN(ARGUS_1990_I283027);

}