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
| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief Xi_c -> xi pi pi
class BELLE_2018_I1698390 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2018_I1698390);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
// projection
declare(UnstableParticles(),"UFS");
// histo
book(_h,1,1,1);
}
void findDecay(int & sign, const Particle & parent, Particles & xi, Particles & pi,
unsigned int & nstable) {
for(const Particle & p : parent.children()) {
if(p.pid()==sign*3312) {
++nstable;
xi.push_back(p);
}
else if(p.pid()==sign*211) {
++nstable;
pi.push_back(p);
}
else if(p.children().empty())
++nstable;
else
findDecay(sign,p,xi,pi,nstable);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for(const Particle & p : apply<UnstableParticles>(event,"UFS").particles(Cuts::abspid==4232)) {
int sign = p.pid()/p.abspid();
Particles xi,pi;
unsigned int nstable(0);
findDecay(sign,p,xi,pi,nstable);
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
if(nstable==3&&xi.size()==1&&pi.size()==2) {
double p1 = boost.transform(pi[0].momentum()).p3().mod();
double p2 = boost.transform(pi[1].momentum()).p3().mod();
double mass = p1>p2 ?
(pi[1].momentum()+xi[0].momentum()).mass() :
(pi[0].momentum()+xi[0].momentum()).mass();
_h->fill(mass);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h);
}
///@}
/// @name Histograms
///@{
Histo1DPtr _h;
///@}
};
RIVET_DECLARE_PLUGIN(BELLE_2018_I1698390);
}
|