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
| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/FastJets.hh"
namespace Rivet {
/// @brief D_1 D*2 decay angle
class CLEO_1990_I281039 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_1990_I281039);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(), "UFS");
// Book histograms
book(_h_D1, 1, 1, 1);
book(_h_D2, 1, 1, 2);
}
/// Recursively walk the decay tree to find decay products of @a p
void findDecayProducts(Particle mother, Particles & dstar, Particles & pi,unsigned int & ncount) {
for(const Particle & p: mother.children()) {
if(p.abspid()==413)
dstar.push_back(p);
else if(p.abspid()==211)
pi.push_back(p);
ncount +=1;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for(const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==425||
Cuts::abspid==10423)) {
// decay products
Particles dstar,pi;
unsigned int ncount=0;
findDecayProducts(p,dstar,pi,ncount);
if(ncount!=2 || dstar.size()!=1 || pi.size()!=1) continue;
if(dstar[0].pid()/p.pid()<0) continue;
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
Vector3 axis = boost.transform(dstar[0].momentum()).p3().unit();
double cosL = axis.dot(p.momentum().p3().unit());
// decay angles
if(p.abspid()==425)
_h_D2->fill(cosL);
else
_h_D1->fill(cosL);
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_D1);
normalize(_h_D2);
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_D1,_h_D2;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(CLEO_1990_I281039);
}
|