Rivet analyses referenceE791_2002_I585322Dalitz plot analysis of $D^+\to K^-\pi^+\pi^+$Experiment: E791 (Fermilab) Inspire ID: 585322 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $D^+\to K^-\pi^+\pi^+$. The data were read from the plots in the paper. Resolution/acceptance effects have been not unfolded and given the agreement with the model in the paper this analysis should only be used for qualitative studies. Source code: E791_2002_I585322.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/DecayedParticles.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5
6namespace Rivet {
7
8
9 /// @brief D+ -> K-pi+pi+
10 class E791_2002_I585322 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(E791_2002_I585322);
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== 411);
24 declare(ufs, "UFS");
25 DecayedParticles DP(ufs);
26 DP.addStable(PID::PI0);
27 declare(DP, "DP");
28 // histos
29 book(_h_low,1,1,1);
30 book(_h_high,1,1,2);
31 book(_dalitz, "dalitz",50,0.,3.1,50,0.3,3.1);
32 }
33
34 /// Perform the per-event analysis
35 void analyze(const Event& event) {
36 static const map<PdgId,unsigned int> & mode = { { 211,2}, {-321,1} };
37 static const map<PdgId,unsigned int> & modeCC = { {-211,2}, { 321,1} };
38 // Loop over D+ mesons
39 DecayedParticles DP = apply<DecayedParticles>(event, "DP");
40 for(unsigned int ix=0;ix<DP.decaying().size();++ix) {
41 int sign = 1;
42 if ( DP.modeMatches(ix,3,mode )) sign = 1;
43 else if( DP.modeMatches(ix,3,modeCC)) sign =-1;
44 else
45 continue;
46 const Particles & pip = DP.decayProducts()[ix].at( sign*211);
47 const Particle & Km = DP.decayProducts()[ix].at(-sign*321)[0];
48 double mplus = (Km.momentum() +pip[0].momentum()).mass2();
49 double mminus = (Km.momentum() +pip[1].momentum()).mass2();
50 if(mplus<mminus) swap(mplus,mminus);
51 _h_low ->fill(mminus);
52 _h_high->fill(mplus );
53 _dalitz->fill(mminus,mplus );
54 _dalitz->fill(mplus ,mminus);
55 }
56 }
57
58
59 /// Normalise histograms etc., after the run
60 void finalize() {
61 normalize(_h_low );
62 normalize(_h_high);
63 normalize(_dalitz);
64 }
65
66 /// @}
67
68
69 /// @name Histograms
70 /// @{
71 Histo1DPtr _h_high,_h_low;
72 Histo2DPtr _dalitz;
73 /// @}
74
75
76 };
77
78
79 RIVET_DECLARE_PLUGIN(E791_2002_I585322);
80
81}
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