Rivet analyses referenceCLEO_2017_I1519168Mass distributions in the decays $D^0\to \pi^+\pi^-\pi^+\pi^-$ and $D^0\to K^+K^-\pi^+\pi^-$Experiment: CLEO (CESR) Inspire ID: 1519168 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Measurement of the mass distributions in the decays $D^0\to \pi^+\pi^-\pi^+\pi^-$ and $D^0\to K^+K^-\pi^+\pi^-$ using data from CLEO. 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: CLEO_2017_I1519168.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 -> K+ K- pi+ pi- and 2pi+2pi-
10 class CLEO_2017_I1519168 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2017_I1519168);
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<8;++ix)
33 book(_h[ix ],1,1,1+ix);
34 for(unsigned int ix=0;ix<6;++ix)
35 book(_h[ix+ 8],2,1,1+ix);
36 for(unsigned int ix=0;ix<4;++ix)
37 book(_h[ix+14],3,1,1+ix);
38 }
39
40
41 /// Perform the per-event analysis
42 void analyze(const Event& event) {
43 // define the decay mode
44 static const map<PdgId,unsigned int> & mode1 = { { 211,2}, { -211,2}};
45 static const map<PdgId,unsigned int> & mode2 = { { 321,1}, { -321,1}, { 211,1}, { -211,1}};
46 DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
47 // loop over particles
48 for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
49 int sign = D0.decaying()[ix].pid()/421;
50 if ( D0.modeMatches(ix,4,mode1)) {
51 const Particles & pip= D0.decayProducts()[ix].at( sign*211);
52 const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
53 bool KSveto=false;
54 set<double> mpm;
55 for(unsigned int ix=0;ix<2;++ix) {
56 for(unsigned int iy=0;iy<2;++iy) {
57 double m2 = (pip[ix].momentum()+pim[iy].momentum()).mass2();
58 double m = sqrt(m2);
59 mpm.insert(m2);
60 if(abs(m-0.497611)<0.0165) KSveto=true;
61 }
62 }
63 if(KSveto) continue;
64 _h[0]->fill(*mpm.begin());
65 _h[1]->fill(*mpm.rbegin());
66 for(const double & m2 : mpm) _h[2]->fill(m2);
67 FourMomentum ppp = pip[0].momentum()+pip[1].momentum();
68 _h[3]->fill(ppp.mass2());
69 FourMomentum pmm = pim[0].momentum()+pim[1].momentum();
70 double m2ppm[2] = {(ppp+pim[0].momentum()).mass2(),(ppp+pim[1].momentum()).mass2()};
71 if(m2ppm[0]>m2ppm[1]) swap(m2ppm[0],m2ppm[1]);
72 _h[4]->fill(m2ppm[0]);
73 _h[5]->fill(m2ppm[1]);
74 double m2mmp[2] = {(pmm+pip[0].momentum()).mass2(),(pmm+pip[1].momentum()).mass2()};
75 if(m2mmp[0]>m2mmp[1]) swap(m2mmp[0],m2mmp[1]);
76 _h[6]->fill(m2mmp[0]);
77 _h[7]->fill(m2ppm[1]);
78 }
79 else if ( D0.modeMatches(ix,4,mode2)) {
80 const Particles & Kp = D0.decayProducts()[ix].at( sign*321);
81 const Particles & Km = D0.decayProducts()[ix].at(-sign*321);
82 const Particles & pip= D0.decayProducts()[ix].at( sign*211);
83 const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
84 double mpipi = (pip[0].momentum()+pim[0].momentum()).mass();
85 if(abs(mpipi-0.497611)<0.0165) continue;
86 _h[ 8]->fill((Kp [0].momentum()+Km [0].momentum()).mass2());
87 _h[ 9]->fill((Kp [0].momentum()+pip[0].momentum()).mass2());
88 _h[10]->fill((Kp [0].momentum()+pim[0].momentum()).mass2());
89 _h[11]->fill((Km [0].momentum()+pip[0].momentum()).mass2());
90 _h[12]->fill((Km [0].momentum()+pim[0].momentum()).mass2());
91 _h[13]->fill(sqr(mpipi));
92 _h[14]->fill((Kp [0].momentum()+Km [0].momentum()+pip[0].momentum()).mass2());
93 _h[15]->fill((Kp [0].momentum()+Km [0].momentum()+pim[0].momentum()).mass2());
94 _h[16]->fill((Kp [0].momentum()+pip[0].momentum()+pim[0].momentum()).mass2());
95 _h[17]->fill((Km [0].momentum()+pip[0].momentum()+pim[0].momentum()).mass2());
96 }
97 }
98 }
99
100
101 /// Normalise histograms etc., after the run
102 void finalize() {
103 for(unsigned int ix=0;ix<18;++ix)
104 normalize(_h[ix],1.,false);
105 }
106
107 /// @}
108
109
110 /// @name Histograms
111 /// @{
112 Histo1DPtr _h[18];
113 /// @}
114
115
116 };
117
118
119 RIVET_DECLARE_PLUGIN(CLEO_2017_I1519168);
120
121}
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