Rivet analyses referenceBABAR_2019_I1691954Mass distributions in the decay $D^0\to K^-\pi^+e^+e^-$Experiment: BABAR (PEP-II) Inspire ID: 1691954 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Kinematic distributions in the decay $D^0\to K^-\pi^+e^+e^-$. Resolution/acceptance effects have been not unfolded. Source code: BABAR_2019_I1691954.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4#include "Rivet/Projections/DecayedParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief D0 -> K- pi+ e+e-
10 class BABAR_2019_I1691954 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2019_I1691954);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22 // Initialise and register projections
23 UnstableParticles ufs = UnstableParticles(Cuts::abspid==421);
24 declare(ufs, "UFS");
25 DecayedParticles D0(ufs);
26 D0.addStable(PID::PI0);
27 D0.addStable(PID::K0S);
28 declare(D0, "D0");
29 for(unsigned int ix=0;ix<2;++ix)
30 book(_h[ix],1,1,1+ix);
31 book(_h[2],2,1,1);
32 }
33
34
35 /// Perform the per-event analysis
36 void analyze(const Event& event) {
37 static const map<PdgId,unsigned int> & mode = { {-321,1}, { 211,1}, {11,1}, {-11,1} };
38 static const map<PdgId,unsigned int> & modeCC = { { 321,1}, {-211,1}, {11,1}, {-11,1} };
39 DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
40 // loop over particles
41 for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
42 int sign = 1;
43 if (D0.decaying()[ix].pid()>0 && D0.modeMatches(ix,4,mode)) {
44 sign=1;
45 }
46 else if (D0.decaying()[ix].pid()<0 && D0.modeMatches(ix,4,modeCC)) {
47 sign=-1;
48 }
49 else
50 continue;
51 const Particle & Kp = D0.decayProducts()[ix].at(-sign*321)[0];
52 const Particle & pim = D0.decayProducts()[ix].at( sign*211)[0];
53 const Particle & ep = D0.decayProducts()[ix].at( 11)[0];
54 const Particle & em = D0.decayProducts()[ix].at(-11)[0];
55 double mee = (em.momentum()+ep.momentum()).mass();
56 if(mee>0.675 && mee<0.875) {
57 _h[1]->fill((Kp.momentum()+pim.momentum()).mass());
58 _h[0]->fill(mee);
59 }
60 if(mee>.2) _h[2]->fill(mee);
61 }
62 }
63
64
65 /// Normalise histograms etc., after the run
66 void finalize() {
67 for(unsigned int ix=0;ix<3;++ix)
68 normalize(_h[ix],1.,false);
69 }
70
71 /// @}
72
73
74 /// @name Histograms
75 /// @{
76 Histo1DPtr _h[3];
77 /// @}
78
79
80 };
81
82
83 RIVET_DECLARE_PLUGIN(BABAR_2019_I1691954);
84
85}
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