Rivet analyses referenceBESIII_2023_I2645182Differenital decay rate in $D^+_s\to \pi^+\pi^- e^+\nu_e$Experiment: BESIII (BEPC) Inspire ID: 2645182 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Differenital decay rate in $D^+_s\to \pi^+\pi^- e^+\nu_e$. Correcvted data read from figure in the paper. Source code: BESIII_2023_I2645182.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4
5namespace Rivet {
6
7
8 /// @brief D_s -> f0 e+ nu_e
9 class BESIII_2023_I2645182 : public Analysis {
10 public:
11
12 /// Constructor
13 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2023_I2645182);
14
15
16 /// @name Analysis methods
17 /// @{
18
19 /// Book histograms and initialise projections before the run
20 void init() {
21 // Initialise and register projections
22 declare(UnstableParticles(Cuts::pid==431), "UFS");
23 // histos
24 book(_h,1,1,1);
25 book(_nDs, "TMP/nDs");
26 }
27
28 // Check for explicit decay into pdgids
29 bool isSemileptonicDecay(const Particle& mother, vector<int> ids) {
30 // Trivial check to ignore any other decays but the one in question modulo photons
31 const Particles children = mother.children(Cuts::pid!=PID::PHOTON);
32 if (children.size()!=ids.size()) return false;
33 // Check for the explicit decay
34 return all(ids, [&](int i){return count(children, hasPID(i))==1;});
35 }
36
37 /// Perform the per-event analysis
38 void analyze(const Event& event) {
39 static const int mesonID=9010221;
40 // Loop over Ds mesons
41 for (const Particle& p : apply<UnstableParticles>(event, "UFS").particles()) {
42 _nDs->fill();
43 Particle f0;
44 if (isSemileptonicDecay(p, {mesonID, PID::POSITRON, PID::NU_E})) {
45 f0 = select(p.children(), Cuts::pid==mesonID)[0];
46 if (f0.children().size()==2 &&
47 f0.children()[1].pid() == -f0.children()[0].pid() &&
48 f0.children()[0].abspid()==211) {
49 _h->fill((p.mom()-f0.mom()).mass2());
50 }
51 }
52 }
53 }
54
55
56 /// Normalise histograms etc., after the run
57 void finalize() {
58 // D_s lifetime pdg2022 (ns)
59 const double tau = 504e-6;
60 scale(_h,1./tau/ *_nDs);
61 }
62
63 /// @}
64
65
66 /// @name Histograms
67 /// @{
68 Histo1DPtr _h;
69 CounterPtr _nDs;
70 /// @}
71
72
73 };
74
75
76 RIVET_DECLARE_PLUGIN(BESIII_2023_I2645182);
77
78}
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