Rivet analyses referenceBESIII_2024_I2819140Exclusive $D^0\to K^-\ell^+\nu_\ell$ and $D^+\to \bar{K}^0\ell^+\nu_\ell$ decaysExperiment: BESIII (BEPC) Inspire ID: 2819140 Status: VALIDATED NOHEPDATA Authors:
Beam energies: ANY Run details:
Differential decay rates for semi-leptonic $D^0\to K^-\ell^+\nu_\ell$ and $D^+\to \bar{K}^0\ell^+\nu_\ell$ decays Source code: BESIII_2024_I2819140.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4
5namespace Rivet {
6
7
8 /// @brief D0 -> K- ell+ nu_ell and D+ -> Kbar0 ell+ nu_ell
9 class BESIII_2024_I2819140 : public Analysis {
10 public:
11
12 /// Constructor
13 RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2024_I2819140);
14
15
16 /// @name Analysis methods
17 /// @{
18
19 /// Book histograms and initialise projections before the run
20 void init() {
21
22 // Initialise and register projections
23 declare(UnstableParticles(Cuts::abspid==411 || Cuts::abspid==421 ), "UFS");
24
25 for(unsigned int ix=0;ix<4;++ix) {
26 book(_h[ix], 1+ix , 1 ,1);
27 if(ix>1) continue;
28 book(_c[ix], "TMP/c_"+toString(ix+1));
29 }
30 }
31
32 // Calculate the Q2 using mother and daugher meson
33 double q2(const Particle& B, int mesonID) {
34 FourMomentum q = B.mom() - select(B.children(), Cuts::pid==mesonID)[0];
35 return q*q;
36 }
37
38 // Check for explicit decay into pdgids
39 bool isSemileptonicDecay(const Particle& mother, vector<int> ids) {
40 // Trivial check to ignore any other decays but the one in question modulo photons
41 const Particles children = mother.children(Cuts::pid!=PID::PHOTON);
42 if (children.size()!=ids.size()) return false;
43 // Check for the explicit decay
44 return all(ids, [&](int i){return count(children, hasPID(i))==1;});
45 }
46
47 /// Perform the per-event analysis
48 void analyze(const Event& event) {
49
50 // Loop over D mesons
51 for (const Particle& p : apply<UnstableParticles>(event, "UFS").particles()) {
52 if(p.pid()==421) {
53 _c[0]->fill();
54 if(isSemileptonicDecay(p, {PID::KMINUS, PID::EPLUS, PID::NU_E})) {
55 _h[0]->fill(q2(p, PID::KMINUS));
56 }
57 else if(isSemileptonicDecay(p, {PID::KMINUS, PID::ANTIMUON, PID::NU_MU})) {
58 _h[1]->fill(q2(p, PID::KMINUS));
59 }
60 }
61 else if(p.pid()==-421) {
62 _c[0]->fill();
63 if(isSemileptonicDecay(p, {PID::KPLUS, PID::EMINUS, PID::NU_EBAR})) {
64 _h[0]->fill(q2(p, PID::KPLUS));
65 }
66 else if(isSemileptonicDecay(p, {PID::KPLUS, PID::MUON, PID::NU_MUBAR})) {
67 _h[1]->fill(q2(p, PID::KPLUS));
68 }
69 }
70 else if(p.pid()==411) {
71 _c[1]->fill();
72 if(isSemileptonicDecay(p, {-311, PID::EPLUS, PID::NU_E})) {
73 _h[2]->fill(q2(p, -311));
74 }
75 else if(isSemileptonicDecay(p, {-311, PID::ANTIMUON, PID::NU_MU})) {
76 _h[3]->fill(q2(p, -311));
77 }
78 else if(isSemileptonicDecay(p, { 130, PID::EPLUS, PID::NU_E})) {
79 _h[2]->fill(q2(p, 130));
80 }
81 else if(isSemileptonicDecay(p, { 130, PID::ANTIMUON, PID::NU_MU})) {
82 _h[3]->fill(q2(p, 130));
83 }
84 else if(isSemileptonicDecay(p, { 310, PID::EPLUS, PID::NU_E})) {
85 _h[2]->fill(q2(p, 310));
86 }
87 else if(isSemileptonicDecay(p, { 310, PID::ANTIMUON, PID::NU_MU})) {
88 _h[3]->fill(q2(p, 310));
89 }
90 }
91 else if(p.pid()==-411) {
92 _c[1]->fill();
93 if(isSemileptonicDecay(p, {311, PID::EMINUS, PID::NU_EBAR})) {
94 _h[2]->fill(q2(p, 311));
95 }
96 else if(isSemileptonicDecay(p, {311, PID::MUON, PID::NU_MUBAR})) {
97 _h[3]->fill(q2(p, 311));
98 }
99 else if(isSemileptonicDecay(p, { 130, PID::EMINUS, PID::NU_EBAR})) {
100 _h[2]->fill(q2(p, 130));
101 }
102 else if(isSemileptonicDecay(p, { 130, PID::MUON, PID::NU_MUBAR})) {
103 _h[3]->fill(q2(p, 130));
104 }
105 else if(isSemileptonicDecay(p, { 310, PID::EMINUS, PID::NU_EBAR})) {
106 _h[2]->fill(q2(p, 310));
107 }
108 else if(isSemileptonicDecay(p, { 310, PID::MUON, PID::NU_MUBAR})) {
109 _h[3]->fill(q2(p, 310));
110 }
111 }
112 }
113 }
114
115
116 /// Normalise histograms etc., after the run
117 void finalize() {
118 // lifetimes from PDG 2022 [ns] (as in paper)
119 double tau[2] = {410.3e-6, 1033e-6};
120 for(unsigned int ix=0;ix<4;++ix)
121 scale(_h[ix],1./tau[ix/2]/ *_c[ix/2]);
122 }
123
124 /// @}
125
126
127 /// @name Histograms
128 /// @{
129 Histo1DPtr _h[4];
130 CounterPtr _c[2];
131 /// @}
132
133
134 };
135
136
137 RIVET_DECLARE_PLUGIN(BESIII_2024_I2819140);
138
139}
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