1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief B->D semileptonic decays
class BELLE_2020_I1796822 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2020_I1796822);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(), "UFS");
// Book histograms
book(_h_mpipi,1,1,1);
book(_h_q2 ,2,1,1);
book(_nB,"/TMP/nB");
}
void findChildren(const Particle & p, unsigned int &ncount,
Particles & pi, Particles & ell, Particles & nu) {
_nB->fill();
for (const Particle &child : p.children()) {
if(child.children().empty()) {
if(child.abspid()==211) {
++ncount;
pi.push_back(child);
}
else if(child.abspid()==11 || child.abspid()==13) {
++ncount;
ell.push_back(child);
}
else if(child.abspid()==12 || child.abspid()==14) {
++ncount;
nu.push_back(child);
}
else if(child.pid()!=22)
++ncount;
}
// veto gamma gamma decaying mesons and K0
else if(child.pid()==111 || child.pid()==221 || child.pid()==331 ||
child.pid()==130 || child.pid()==310) {
++ncount;
}
else
findChildren(child,ncount,pi,ell,nu);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for(const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::pid==PID::BPLUS)) {
Particles pi,ell,nu;
unsigned int ncount = 0;
findChildren(p,ncount,pi,ell,nu);
// check the decay
// 4 outgoing
if(ncount!=4) continue;
// including pi+ pi-
if(pi.size()!=2 || pi[0].pid() != -pi[1].pid()) continue;
// and ell- nubar or ell+ nu
if(ell.size()!=1 || nu.size()!=1) continue;
int inu = ell[0].abspid()+1;
if(ell[0].pid()>0) inu *=-1;
if(nu[0].pid()!=inu) continue;
// fill histos
// m pipi
FourMomentum ppi = pi[0].momentum()+pi[1].momentum();
_h_mpipi->fill(ppi.mass());
// q2
FourMomentum q = p.momentum() - ppi;
_h_q2->fill(q.mass2());
}
}
/// Normalise histograms etc., after the run
void finalize() {
scale(_h_mpipi,1e5/ *_nB);
scale(_h_q2 ,1e5/ *_nB);
}
///@}
/// @name Histograms
///@{
Histo1DPtr _h_mpipi,_h_q2;
CounterPtr _nB;
///@}
};
RIVET_DECLARE_PLUGIN(BELLE_2020_I1796822);
}
|