Rivet analyses referenceBABAR_2016_I1409292Mass spectra in $B^+\to K^+\pi^+\pi^-\gamma$ decaysExperiment: BABAR (PEP-II) Inspire ID: 1409292 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Mass spectra in $B^+\to K^+\pi^+\pi^-\gamma$ decays measured by BABAR. Useful for testing the implementation of these decays Source code: BABAR_2016_I1409292.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 B+ -> K+ pi+ pi- gamma
10 class BABAR_2016_I1409292 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2016_I1409292);
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==521);
24 declare(ufs, "UFS");
25 DecayedParticles BP(ufs);
26 BP.addStable(PID::PI0);
27 declare(BP, "BP");
28 // histograms
29 for(unsigned int ix=0;ix<2;++ix) {
30 book(_h[ix],1+ix,1,1);
31 }
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}, {-211,1}, {22,1}};
38 static const map<PdgId,unsigned int> & modeCC = { {-321,1},{ 211,1}, {-211,1}, {22,1}};
39 DecayedParticles BP = apply<DecayedParticles>(event, "BP");
40 // loop over particles
41 for(unsigned int ix=0;ix<BP.decaying().size();++ix) {
42 int sign = 1;
43 if (BP.decaying()[ix].pid()>0 && BP.modeMatches(ix,4,mode)) {
44 sign=1;
45 }
46 else if (BP.decaying()[ix].pid()<0 && BP.modeMatches(ix,4,modeCC)) {
47 sign=-1;
48 }
49 else
50 continue;
51 const Particle & Kp = BP.decayProducts()[ix].at( sign*321)[0];
52 const Particle & pip = BP.decayProducts()[ix].at( sign*211)[0];
53 const Particle & pim = BP.decayProducts()[ix].at(-sign*211)[0];
54 _h[0]->fill((Kp.momentum()+pim.momentum()+pip.momentum()).mass());
55 _h[1]->fill((Kp.momentum()+pim.momentum()).mass());
56 }
57 }
58
59
60 /// Normalise histograms etc., after the run
61 void finalize() {
62 for(unsigned int ix=0;ix<2;++ix) {
63 normalize(_h[ix],1.,false);
64 }
65 }
66
67 /// @}
68
69
70 /// @name Histograms
71 /// @{
72 Histo1DPtr _h[2];
73 /// @}
74
75
76 };
77
78
79 RIVET_DECLARE_PLUGIN(BABAR_2016_I1409292);
80
81}
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