Rivet analyses referenceCLEOC_2007_I749602Dalitz plot analysis of $D^+\to \pi^+\pi^+\pi^-$Experiment: CLEOC (CESR) Inspire ID: 749602 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decay $D^+\to \pi^+\pi^+\pi^-$. The data were read from the plots in the paper and the backgrounds subtracted. 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: CLEOC_2007_I749602.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 D+ -> pi+pi+pi-
10 class CLEOC_2007_I749602 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(CLEOC_2007_I749602);
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 DP.addStable(PID::K0S);
28 DP.addStable(PID::ETA);
29 DP.addStable(PID::ETAPRIME);
30 declare(DP, "DP");
31 // histos
32 book(_h_pippim,1,1,1);
33 book(_h_pippip,1,1,2);
34 book(_dalitz, "dalitz",50,0.,1.8,50,0.0,3.1);
35 }
36
37 /// Perform the per-event analysis
38 void analyze(const Event& event) {
39 static const map<PdgId,unsigned int> & mode = { { 211,2},{-211,1}};
40 static const map<PdgId,unsigned int> & modeCC = { { 211,1},{-211,2}};
41 DecayedParticles DP = apply<DecayedParticles>(event, "DP");
42 // loop over particles
43 for(unsigned int ix=0;ix<DP.decaying().size();++ix) {
44 int sign = 1;
45 if (DP.decaying()[ix].pid()>0 && DP.modeMatches(ix,3,mode)) {
46 sign=1;
47 }
48 else if (DP.decaying()[ix].pid()<0 && DP.modeMatches(ix,3,modeCC)) {
49 sign=-1;
50 }
51 else
52 continue;
53 const Particles & pip= DP.decayProducts()[ix].at( sign*211);
54 const Particles & pim= DP.decayProducts()[ix].at(-sign*211);
55 double m1 = (pim[0].momentum()+pip[0].momentum()).mass2();
56 double m2 = (pim[0].momentum()+pip[1].momentum()).mass2();
57 double m3 = (pip[0].momentum()+pip[1].momentum()).mass2();
58 if(m1>m2) swap(m1,m2);
59 _dalitz->fill(m1,m2);
60 // K_S0 veto
61 if(m1<0.2 || m1>0.3) {
62 _h_pippim->fill(m1);
63 _h_pippim->fill(m2);
64 _h_pippip->fill(m3);
65 }
66 }
67 }
68
69
70 /// Normalise histograms etc., after the run
71 void finalize() {
72 normalize(_h_pippim);
73 normalize(_h_pippip);
74 normalize(_dalitz);
75 }
76
77 /// @}
78
79
80 /// @name Histograms
81 /// @{
82 Histo1DPtr _h_pippim,_h_pippip;
83 Histo2DPtr _dalitz;
84 /// @}
85
86
87 };
88
89
90 RIVET_DECLARE_PLUGIN(CLEOC_2007_I749602);
91
92}
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