Rivet analyses referenceFOCUS_2004_I654030Dalitz decay of $D^+$ and $D^+_s\to K^+\pi^+\pi^-$Experiment: FOCUS (Fermilab) Inspire ID: 654030 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decays $D^+$ and $D^+_s\to K^+\pi^+\pi^-$ by FOCUS. The data were read from the plots in the paper and therefore for some points the error bars are the size of the point. It is also not clear that any resolution effects have been unfolded. Source code: FOCUS_2004_I654030.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+/Ds+ -> K+ pi+ pi-
10 class FOCUS_2004_I654030 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(FOCUS_2004_I654030);
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 or
24 Cuts::abspid==431);
25 declare(ufs, "UFS");
26 DecayedParticles DD(ufs);
27 DD.addStable(PID::PI0);
28 DD.addStable(PID::K0S);
29 declare(DD, "DD");
30 // histograms
31 for(unsigned int ix=0;ix<2;++ix) {
32 book(_h_Kpim[ix],1+ix,1,1);
33 book(_h_pipi[ix],1+ix,1,2);
34 book(_dalitz[ix],"dalitz_"+to_str(ix+1),50,0.3,3.5,50,0.,2.3);
35 }
36 }
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 static const map<PdgId,unsigned int> & mode = { { 211,1}, { 321,1}, {-211,1}};
41 static const map<PdgId,unsigned int> & modeCC = { {-211,1}, {-321,1}, { 211,1}};
42 DecayedParticles DD = apply<DecayedParticles>(event, "DD");
43 // loop over particles
44 for(unsigned int ix=0;ix<DD.decaying().size();++ix) {
45 int sign = 1;
46 if (DD.decaying()[ix].pid()>0 && DD.modeMatches(ix,3,mode)) {
47 sign=1;
48 }
49 else if (DD.decaying()[ix].pid()<0 && DD.modeMatches(ix,3,modeCC)) {
50 sign=-1;
51 }
52 else
53 continue;
54 const Particle & Kp = DD.decayProducts()[ix].at( sign*321)[0];
55 const Particle & pip = DD.decayProducts()[ix].at( sign*211)[0];
56 const Particle & pim = DD.decayProducts()[ix].at(-sign*211)[0];
57 double mm = (Kp .momentum()+pim.momentum()).mass2();
58 double mpipi = (pip.momentum()+pim.momentum()).mass2();
59 unsigned int iloc = DD.decaying()[ix].abspid()==411 ? 0 : 1;
60 _dalitz[iloc]->fill(mm,mpipi);
61 _h_pipi[iloc]->fill(mpipi);
62 _h_Kpim[iloc]->fill(mm);
63 }
64 }
65
66
67 /// Normalise histograms etc., after the run
68 void finalize() {
69 for(unsigned int ix=0;ix<2;++ix) {
70 normalize(_h_Kpim[ix]);
71 normalize(_h_pipi[ix]);
72 normalize(_dalitz[ix]);
73 }
74 }
75
76 /// @}
77
78
79 /// @name Histograms
80 /// @{
81 Histo1DPtr _h_Kpim[2],_h_pipi[2];
82 Histo2DPtr _dalitz[2];
83 /// @}
84
85
86 };
87
88
89 RIVET_DECLARE_PLUGIN(FOCUS_2004_I654030);
90
91}
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