rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

BABAR_2008_I790461

Kinematic distributions in $D^+_s\to K^+K^- e^+\nu_e$
Experiment: BABAR (PEP-II)
Inspire ID: 790461
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.D 78 (2008) 051101
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing DS

Measurement of the kinematic distributions in $D^+_s\to K^+K^- e^+\nu_e$ by BaBar. N.B. the plots where read from the paper and may not have been corrected for acceptance.

Source code: BABAR_2008_I790461.cc 
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"

namespace Rivet {


  /// @brief D_s+ -> K+K- e+ nu_e
  class BABAR_2008_I790461 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2008_I790461);


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

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::pid==431);
      declare(ufs, "UFS");
      DecayedParticles DS(ufs);
      DS.addStable(PID::PI0);
      DS.addStable(PID::K0S);
      DS.addStable(PID::ETA);
      DS.addStable(PID::ETAPRIME);
      declare(DS, "DS");
      
      // Book histograms
      book(_h[0],1,1,1);
      for(unsigned int ix=0;ix<4;++ix)
	book(_h[ix+1],2,1,1+ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode = { { 321,1}, {-321,1}, {-11,1}, { 12,1}};
      DecayedParticles DS = apply<DecayedParticles>(event, "DS");
      // loop over particles
      for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
	if(!DS.modeMatches(ix,4,mode)) continue;
	const Particle & Kp = DS.decayProducts()[ix].at( 321)[0];
	const Particle & Km = DS.decayProducts()[ix].at(-321)[0];
	const Particle & ep = DS.decayProducts()[ix].at( -11)[0];
	const Particle & nue= DS.decayProducts()[ix].at(  12)[0];
	FourMomentum pPhi = Kp.momentum()+Km.momentum(); 
	_h[0]->fill(pPhi.mass());
	FourMomentum qq = DS.decaying()[ix].momentum()-pPhi;
	_h[1]->fill(qq.mass2());
	// boost momenta to DS rest frame
	LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(DS.decaying()[ix].momentum().betaVec());
	FourMomentum pPHI = boost.transform(pPhi);
	Matrix3 ptoz(-pPHI.p3().unit(), Vector3(0,0,1));
	boost.preMult(ptoz);
	// the momenta in frane to W along z
	FourMomentum pD  = boost.transform(DS.decaying()[ix].momentum());
	FourMomentum pKp = boost.transform(Kp .momentum());
	FourMomentum pKm = boost.transform(Km .momentum());
	FourMomentum pe  = boost.transform(ep .momentum());
	FourMomentum pnu = boost.transform(nue.momentum());
	pPhi = pKp+pKm;
	qq = pD-pPhi;
	LorentzTransform boostK = LorentzTransform::mkFrameTransformFromBeta(pPhi.betaVec());
	Vector3 axisK = boostK.transform(pKp).p3().unit();
	_h[3]->fill(axisK.dot(pPhi.p3().unit()));
	LorentzTransform boostW = LorentzTransform::mkFrameTransformFromBeta(  qq.betaVec());
	Vector3 axisE = boostW.transform(pe).p3().unit();
	_h[2]->fill(axisE.dot(qq.p3().unit()));
	axisK.setZ(0.);
	axisE.setZ(0.);
	double chi = atan2(axisE.cross(axisK).dot(qq.p3().unit()), axisE.dot(axisK));
	_h[4]->fill(chi);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<5;++ix)
	normalize(_h[ix]);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[5];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BABAR_2008_I790461);

}