Rivet analyses

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

namespace Rivet {


  /// @brief B -> e spectrum
  class ARGUS_1993_I357133 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1993_I357133);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // projections
      declare(UnstableParticles(), "UFS");
      // histograms
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h[ix], 1 + ix, 1, 1);
      }
      book(_c, "TMP/nb");
    }

    void findDecayProducts(const Particle& parent,
                           vector<Particles>& em,
                           vector<Particles>& ep,
                           vector<Particles>& nue,
                           vector<Particles>& nueBar,
                           bool& charm,
                           bool secondary) {
      for (const Particle& p : parent.children()) {
        if (PID::isCharmHadron(p.pid())) {
          charm = true;
          findDecayProducts(p, em, ep, nue, nueBar, charm, true);
        }
        else if (p.pid() == PID::EMINUS) {
          em[secondary].push_back(p);
        }
        else if (p.pid() == PID::EPLUS) {
          ep[secondary].push_back(p);
        }
        else if (p.pid() == PID::NU_E) {
          nue[secondary].push_back(p);
        }
        else if (p.pid() == PID::NU_EBAR) {
          nueBar[secondary].push_back(p);
        }
        else if (PID::isBottomHadron(p.pid())) {
          findDecayProducts(p, em, ep, nue, nueBar, charm, false);
        }
        else if (!PID::isHadron(p.pid())) {
          findDecayProducts(p, em, ep, nue, nueBar, charm, secondary);
        }
      }
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::pid == 300553)) {
        // boost to rest frame
        LorentzTransform cms_boost;
        if (p.p3().mod() > 1 * MeV) {
          cms_boost = LorentzTransform::mkFrameTransformFromBeta(p.mom().betaVec());
        }
        // loop over decay products
        for (const Particle& p2 : p.children()) {
          if (p2.abspid() == 511 || p2.abspid() == 521) {
            _c->fill();
            // find decay products
            bool charm = false;
            vector<Particles> em(2), ep(2), nue(2), nueBar(2);
            findDecayProducts(p2, em, ep, nue, nueBar, charm, false);
            for (unsigned int isec = 0; isec < 2; ++isec) {
              FourMomentum pl, pnu;
              if (em[isec].size() == 1 && nueBar[isec].size() == 1
                  && em[isec][0].pid() + 1 == -nueBar[isec][0].pid()) {
                pl = cms_boost.transform(em[isec][0].mom());
                pnu = cms_boost.transform(nueBar[isec][0].mom());
              }
              else if (ep[isec].size() == 1 && nue[isec].size() == 1
                       && nue[isec][0].pid() == -ep[isec][0].pid() + 1) {
                pl = cms_boost.transform(ep[isec][0].mom());
                pnu = cms_boost.transform(nue[isec][0].mom());
              }
              else {
                continue;
              }
              _h[isec]->fill(pl.p3().mod());
            }
          }
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h, 1.0 / *_c);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[2];
    CounterPtr _c;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(ARGUS_1993_I357133);

}