Rivet analyses

Rate and momentum spectra for anti-deuteron production in Υ(1, 2, 3S) decays and nearby continuum

Experiment: BABAR (PEP-II)

Inspire ID: 1286317

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D89 (2014) no.11, 111102

Beams: e+ e-

Beam energies: (4.7, 4.7); (5.0, 5.0); (5.2, 5.2); (5.3, 5.3)GeV

Run details: - e+e- to hadrons via Upsilon(1,2,3S) and continuum at 10.58 GeV

Measurement of the branching ratios momentum spectra for anti-deuteron production in Υ(1, 2, 3S) decays, together with the cross section and momentum spectrum for anti-deuteron production in the continuum

Source code:BABAR_2014_I1286317.cc

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

namespace Rivet {


  /// @brief anti-deuteron spectrum in upslion decays
  class BABAR_2014_I1286317 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2014_I1286317);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      declare(UnstableParticles(), "UFS");
      // histograms
      book(_h_p[0],6,1,1);
      book(_h_p[1],6,2,1);
      book(_h_p[2],6,3,1);
      book(_h_p[3],6,4,1);
      book(_h_r[0],1,1,1);
      book(_h_r[1],2,1,1);
      book(_h_r[2],3,1,1);
      book(_h_r[3],5,1,1);
      book(_h_r[4],4,1,1);
      book(_w[0],"TMP/w_0");
      book(_w[1],"TMP/w_1");
      book(_w[2],"TMP/w_2");
      book(_w[3],"TMP/w_3");
    }

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

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // find upsilon states
      UnstableParticles  ufs = apply<UnstableParticles>(event, "UFS");
      Particles ups = ufs.particles(Cuts::pid==553||Cuts::pid==100553||Cuts::pid==200553);
      // none, then continuum event
      if(ups.empty()) {
    Particles deut = ufs.particles(Cuts::pid==_did);
    _w[3]->fill();
    for(const Particle& p : deut) {
      double mom = p.momentum().p3().mod();
      _h_p[3]->fill(mom);
      _h_r[3]->fill("10.58"s);
      _h_r[4]->fill("10.58"s);
    }
      }
      // upsilon decays
      else {
    for(const Particle & Y : ups ) {
      unsigned int ihist=2;
      if(Y.pid()==100553) {
        ihist=1;
      }
      else if(Y.pid()==200553) {
        ihist=0;
      }
      _w  [ihist]->fill();
      Particles deut;
      findDecayProducts(Y, deut);
      if(deut.empty()) continue;
      LorentzTransform boost;
      if (Y.p3().mod() > 1*MeV)
        boost = LorentzTransform::mkFrameTransformFromBeta(Y.momentum().betaVec());
      for(const Particle& p : deut) {
        double mom = boost.transform(p.momentum()).p3().mod();
        _h_r[ihist]->fill("10.58"s);
        _h_p[ihist]->fill(mom);
        _w  [ihist]->fill();
      }
    }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // upsilon decays
      for(unsigned int ix=0;ix<3;++ix) {
    if(_w[ix]->effNumEntries()<=0.) continue;
    scale(_h_p[ix],1e6/ *_w[ix]);
    scale(_h_r[ix],1./ *_w[ix]);
    Histo1DPtr _h_p[4],_h_r[5];
    CounterPtr _w[4];
      }
      // continuum
      if(_w[3]->effNumEntries()>0.) {
    scale(_h_p[3], crossSection()/sumOfWeights()/femtobarn);
    scale(_h_r[4], crossSection()/sumOfWeights()/femtobarn);
    scale(_h_r[3],1./ *_w[3]);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_p[4];
    BinnedHistoPtr<string> _h_r[5];
    CounterPtr _w[4];

    // deuteron id code
    static const int _did = -1000010020;
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BABAR_2014_I1286317);

}