|
|
Rivet analyses reference
BESIII_2021_I1870388
$\chi_{c(0,1,2)}\to n K^0_S\bar{\Lambda}^0$ + c.c
Experiment: BESIII (BEPC)
Inspire ID: 1870388
Status: VALIDATED NOHEPDATA
Authors:
References:
Beams: * *
Beam energies: ANY
Run details:
- Any process producing chi_c originally e+e-
Measurement of the mass distributions in the decays $\chi_{c(0,1,2)}\to n K^0_S\bar{\Lambda}^0$ + c.c. The data were read from the plots in the paper and may not be corrected for efficiency or background.
Source code:
BESIII_2021_I1870388.cc
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"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief chi_c -> n K0S Lambdabar +cc
class BESIII_2021_I1870388 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2021_I1870388);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
UnstableParticles ufs = UnstableParticles(Cuts::pid==20443 or
Cuts::pid==445 or
Cuts::pid==10441);
declare(ufs, "UFS");
DecayedParticles chi(ufs);
chi.addStable( PID::PI0);
chi.addStable( PID::K0S);
chi.addStable( PID::ETA);
chi.addStable( PID::ETAPRIME);
chi.addStable( PID::LAMBDA);
chi.addStable(-PID::LAMBDA);
declare(chi, "chi");
// histograms
for(unsigned int ix=0;ix<3;++ix) {
book(_dalitz[ix], "dalitz_"+toString(ix+1),50,2.,7.,50,2.,6.2);
for(unsigned int iy=0;iy<3;++iy)
book(_h[ix][iy],ix+1,1,iy+1);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 2112,1}, {-3122,1}, { 310,1} };
static const map<PdgId,unsigned int> & modeCC = { {-2112,1}, { 3122,1}, { 310,1} };
DecayedParticles chi = apply<DecayedParticles>(event, "chi");
// loop over particles
for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
int sign=1;
if(chi.modeMatches(ix,3,mode)) {
sign = 1;
}
else if(chi.modeMatches(ix,3,modeCC)) {
sign = -1;
}
else continue;
unsigned int iloc = chi.decaying()[ix].pid()==10441 ? 0 : chi.decaying()[ix].pid()==445 ? 2 : 1;
const Particle & KS0 = chi.decayProducts()[ix].at( 310)[0];
const Particle & nn = chi.decayProducts()[ix].at( sign*2112)[0];
const Particle & lbar = chi.decayProducts()[ix].at(-sign*3122)[0];
double mnLam = (nn .momentum()+lbar.momentum()).mass2();
double mnK = (nn .momentum()+ KS0.momentum()).mass2();
double mKLam = (lbar.momentum()+ KS0.momentum()).mass2();
_h[iloc][0]->fill(sqrt(mnLam));
_h[iloc][1]->fill(sqrt(mnK ));
_h[iloc][2]->fill(sqrt(mKLam));
_dalitz[iloc]->fill(mKLam,mnK);
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<3;++ix) {
normalize(_dalitz[ix]);
for(unsigned int iy=0;iy<3;++iy)
normalize(_h[ix][iy]);
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[3][3];
Histo2DPtr _dalitz[3];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2021_I1870388);
}
|
|