Rivet analyses referenceBESIII_2022_I2615968Dalitz plot analysis of $D^0\to K^0_{S,L}\pi^+\pi^-$Experiment: BESIII (BEPC) Inspire ID: 2615968 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of Kinematic distributions in the decay $D^0\to K^0_S\pi^+\pi^-$ by BESIII. The data were read from the plots in the paper and resolution/acceptance effects may not have been unfolded. Source code: BESIII_2022_I2615968.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 -> KS0, KL0 pi+ pi-
10 class BESIII_2022_I2615968 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2022_I2615968);
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 D0.addStable(PID::ETA);
29 D0.addStable(PID::ETAPRIME);
30 declare(D0, "D0");
31 // Histograms
32 for(unsigned int ix=0;ix<2;++ix)
33 for(unsigned int iy=0;iy<3;++iy)
34 book(_h[ix][iy],1+ix,1,1+iy);
35 }
36
37
38 /// Perform the per-event analysis
39 void analyze(const Event& event) {
40 // // define the decay mode
41 static const map<PdgId,unsigned int> & mode1 = { { 310,1}, { 211,1},{-211,1}};
42 static const map<PdgId,unsigned int> & mode2 = { { 130,1}, { 211,1},{-211,1}};
43 DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
44 // loop over particles
45 for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
46 int sign = D0.decaying()[ix].pid()/421;
47 int imode = 0;
48 // KS0 pi+pi-
49 if (D0.modeMatches(ix,3,mode1) ) imode=0;
50 else if (D0.modeMatches(ix,3,mode2) ) imode=1;
51 else continue;
52 const Particle & pip= D0.decayProducts()[ix].at( sign*211)[0];
53 const Particle & pim= D0.decayProducts()[ix].at(-sign*211)[0];
54 const Particle & K0 = D0.decayProducts()[ix].at( imode==0 ? 310 : 130)[0];
55 double mminus = (pim.momentum()+K0.momentum() ).mass2();
56 double mplus = (pip.momentum()+K0.momentum() ).mass2();
57 double mpipi = (pip.momentum()+pim.momentum()).mass2();
58 _h[imode][0]->fill(mplus );
59 _h[imode][1]->fill(mminus);
60 _h[imode][2]->fill(mpipi );
61 }
62 }
63
64
65 /// Normalise histograms etc., after the run
66 void finalize() {
67 for(unsigned int ix=0;ix<2;++ix)
68 for(unsigned int iy=0;iy<3;++iy)
69 normalize(_h[ix][iy],1.,false);
70 }
71
72 /// @}
73
74
75 /// @name Histograms
76 /// @{
77 Histo1DPtr _h[2][3];
78 /// @}
79
80
81 };
82
83
84 RIVET_DECLARE_PLUGIN(BESIII_2022_I2615968);
85
86}
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