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
| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief J/Psi chi_c charged particle multiplicities
class BESIII_2020_I1800404 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2020_I1800404);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(Cuts::pid==443 or Cuts::pid==445 or Cuts::pid==10441 or Cuts::pid==20443),"UFS");
// histograms
book(_h_chi0,1,1,1);
book(_h_chi1,1,1,2);
book(_h_chi2,1,1,3);
book(_h_jpsi[0],2,1,1);
book(_h_jpsi[1],2,1,2);
}
void findChildren(const Particle & p, int & nCharged) {
for( const Particle &child : p.children()) {
if(child.children().empty()) {
if(PID::isCharged(child.pid())) ++nCharged;
}
else
findChildren(child,nCharged);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// loop over particles
for( const Particle & p : apply<UnstableParticles>(event, "UFS").particles()) {
// skip radiative modes
if(p.children().size()==2) {
if(p.children()[0].pid()==PID::GAMMA) {
if(p.children()[1].pid()==PID::GAMMA ||
p.children()[1].pid()==PID::JPSI) continue;
}
if(p.children()[1].pid()==PID::GAMMA) {
if(p.children()[0].pid()==PID::GAMMA ||
p.children()[0].pid()==PID::JPSI) continue;
}
}
// get the charged particle multiplicity
int nCharged(0);
findChildren(p,nCharged);
if(p.pid()==PID::JPSI) {
_h_jpsi[0]->fill(nCharged);
_h_jpsi[1]->fill(nCharged);
}
else if(p.pid()==10441)
_h_chi0->fill(nCharged);
else if(p.pid()==20443)
_h_chi1->fill(nCharged);
else if(p.pid()==445)
_h_chi2->fill(nCharged);
}
}
/// Normalise histograms etc., after the run
void finalize() {
// percentage and bin width
normalize(_h_jpsi[0],200.);
normalize(_h_jpsi[1],200.);
normalize(_h_chi0 ,200.);
normalize(_h_chi1 ,200.);
normalize(_h_chi2 ,200.);
}
///@}
/// @name Histograms
///@{
Histo1DPtr _h_jpsi[2],_h_chi0,_h_chi1,_h_chi2;
///@}
};
RIVET_DECLARE_PLUGIN(BESIII_2020_I1800404);
}
|