rivet is hosted by Hepforge, IPPP Durham

Rivet analyses reference

BABAR_2011_I897848

Mass distributions in $B^0\to K^+\pi^-\pi^0$ decays
Experiment: BABAR (PEP-II)
Inspire ID: 897848
Status: VALIDATED NOHEPDATA
Authors:
  • Peter Richardson
References:
  • Phys.Rev.D 83 (2011) 112010
Beams: * *
Beam energies: ANY
Run details:
  • Any process producing B0 mesons, originally e+e- at Upsilon(4S)

Measurements of mass distributions in $B^0\to K^+\pi^-\pi^0$ decays. The data were read from the plots in the paper and the backgrounds given subtracted.

Source code: BABAR_2011_I897848.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
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"

namespace Rivet {


  /// @brief B0 -> K+ pi- pi0
  class BABAR_2011_I897848 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2011_I897848);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid==511);
      declare(ufs, "UFS");
      DecayedParticles B0(ufs);
      B0.addStable(PID::PI0);
      declare(B0, "B0");
      // histograms
      for(unsigned int ix=0;ix<3;++ix) {
	for(unsigned int iy=0;iy<2;++iy) {
	  book(_h[ix][iy],1+ix,1,1+iy);
	}
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode   = { { 321,1},{-211,1}, { 111,1}};
      static const map<PdgId,unsigned int> & modeCC = { {-321,1},{ 211,1}, { 111,1}};
      DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
      // loop over particles
      for(unsigned int ix=0;ix<B0.decaying().size();++ix) {
      	int sign = 1;
      	if (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode)) {
      	  sign=1;
      	}
      	else if  (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,modeCC)) {
      	  sign=-1;
      	}
      	else
      	  continue;
	const Particle & Kp  = B0.decayProducts()[ix].at( sign*321)[0];
	const Particle & pim = B0.decayProducts()[ix].at(-sign*211)[0];
	const Particle & pi0 = B0.decayProducts()[ix].at(      111)[0];
	double mpipi = (pim.momentum()+pi0.momentum()).mass();
	_h[0][0]->fill(mpipi);
	if(mpipi<1.8) _h[0][1]->fill(mpipi);
	double mKpi  = (Kp.momentum()+pi0.momentum()).mass();
	_h[1][0]->fill(mKpi);
	if(mKpi<1.8) _h[1][1]->fill(mKpi);
	mKpi  = (Kp.momentum()+pim.momentum()).mass();
	_h[2][0]->fill(mKpi);
	if(mKpi<1.8) _h[2][1]->fill(mKpi);
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<3;++ix) {
	for(unsigned int iy=0;iy<2;++iy) {
	  normalize(_h[ix][iy],1.,false);
	}
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[3][2];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BABAR_2011_I897848);

}