Rivet analyses referenceBELLE_2024_I2810686Differential branching ratio in $B^0\to\pi^-\ell^+\nu_\ell$ and $B^+\to\rho^0\ell^+\nu_\ell$Experiment: BELLE (KEKB) Inspire ID: 2810686 Status: VALIDATED NOHEPDATA Authors:
Beams: * * Beam energies: ANY Run details:
Differential branching ratio in $B^0\to\pi^-\ell^+\nu_\ell$ and $B^+\to\rho^0\ell^+\nu_\ell$ Source code: BELLE_2024_I2810686.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4
5namespace Rivet {
6
7
8 /// @brief B0 -> pi- and B+ rho0 semi-leptonic
9 class BELLE_2024_I2810686 : public Analysis {
10 public:
11
12 /// Constructor
13 RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2024_I2810686);
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(), "UFS");
24 for(unsigned int ix=0;ix<2;++ix) {
25 book(_h[ix],1,1,1+ix);
26 book(_c[ix],"TMP/c_"+toString(ix));
27 }
28 }
29
30 // Calculate the Q2 using mother and daugher meson
31 double q2(const Particle& B, int mesonID) {
32 FourMomentum q = B.mom() - select(B.children(), Cuts::pid==mesonID)[0];
33 return q*q;
34 }
35
36 // Check for explicit decay into pdgids
37 bool isSemileptonicDecay(const Particle& mother, vector<int> ids) {
38 // Trivial check to ignore any other decays but the one in question modulo photons
39 const Particles children = mother.children(Cuts::pid!=PID::PHOTON);
40 if (children.size()!=ids.size()) return false;
41 // Check for the explicit decay
42 return all(ids, [&](int i){return count(children, hasPID(i))==1;});
43 }
44
45 /// Perform the per-event analysis
46 void analyze(const Event& event) {
47 // Loop over B0 Mesons
48 for(const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==PID::B0)) {
49 _c[0]->fill();
50 if(p.pid()<0) {
51 if (isSemileptonicDecay(p, {PID::PIPLUS, PID::ELECTRON, PID::NU_EBAR}) ||
52 isSemileptonicDecay(p, {PID::PIPLUS, PID::MUON, PID::NU_MUBAR})) {
53 _h[0]->fill(q2(p, PID::PIPLUS));
54 }
55 }
56 else {
57 if (isSemileptonicDecay(p, {PID::PIMINUS, PID::POSITRON, PID::NU_E }) ||
58 isSemileptonicDecay(p, {PID::PIMINUS, PID::ANTIMUON, PID::NU_MU})) {
59 _h[0]->fill(q2(p, PID::PIMINUS));
60 }
61 }
62 }
63 for(const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==PID::BPLUS)) {
64 _c[1]->fill();
65 if(p.pid()<0) {
66 if (isSemileptonicDecay(p, {PID::RHO0, PID::ELECTRON, PID::NU_EBAR}) ||
67 isSemileptonicDecay(p, {PID::RHO0, PID::MUON, PID::NU_MUBAR})) {
68 _h[1]->fill(q2(p, PID::RHO0));
69 }
70 }
71 else {
72 if (isSemileptonicDecay(p, {PID::RHO0, PID::POSITRON, PID::NU_E }) ||
73 isSemileptonicDecay(p, {PID::RHO0, PID::ANTIMUON, PID::NU_MU})) {
74 _h[1]->fill(q2(p, PID::RHO0));
75 }
76 }
77 }
78 }
79
80
81 /// Normalise histograms etc., after the run
82 void finalize() {
83 for(unsigned int ix=0;ix<2;++ix) {
84 scale(_h[ix], 0.5e4/ *_c[ix]);
85 }
86 }
87
88 /// @}
89
90
91 /// @name Histograms
92 /// @{
93 Histo1DPtr _h[2];
94 CounterPtr _c[2];
95 /// @}
96
97
98 };
99
100
101 RIVET_DECLARE_PLUGIN(BELLE_2024_I2810686);
102
103}
|