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
111
112 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief D -> pi pi semileptonic
class BESIII_2019_I1694530 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2019_I1694530);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::pid==411 ||Cuts::pid==421);
declare(ufs, "UFS");
DecayedParticles DD(ufs);
DD.addStable(PID::PI0);
DD.addStable(PID::K0S);
DD.addStable(PID::ETA);
DD.addStable(PID::ETAPRIME);
declare(DD, "DD");
// Book histograms
for(unsigned int ix=0;ix<10;++ix)
book(_h[ix],1,1,1+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode1 = { { 111,1}, {-211,1}, {-11,1}, { 12,1}};
static const map<PdgId,unsigned int> & mode2 = { { 211,1}, {-211,1}, {-11,1}, { 12,1}};
DecayedParticles DD = apply<DecayedParticles>(event, "DD");
// loop over particles
for(unsigned int ix=0;ix<DD.decaying().size();++ix) {
Particle pi2;
int imode=-1;
if (DD.decaying()[ix].pid()==421 && DD.modeMatches(ix,4,mode1)) {
pi2= DD.decayProducts()[ix].at(111)[0];
imode=0;
}
else if(DD.decaying()[ix].pid()==411 && DD.modeMatches(ix,4,mode2)) {
pi2= DD.decayProducts()[ix].at(211)[0];
imode=5;
}
else continue;
const Particle & pim= DD.decayProducts()[ix].at(-211)[0];
if (imode==5 && abs((pi2.momentum()+pim.momentum()).mass()-.497611)<0.07) continue;
const Particle & ep = DD.decayProducts()[ix].at(-11)[0];
const Particle & nue= DD.decayProducts()[ix].at( 12)[0];
FourMomentum pRho = pi2.momentum()+pim.momentum();
_h[imode]->fill(pRho.mass());
FourMomentum qq = DD.decaying()[ix].momentum()-pRho;
_h[imode+1]->fill(qq.mass2());
// boost momenta to D rest frame
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(DD.decaying()[ix].momentum().betaVec());
FourMomentum pPP = boost.transform(pRho);
Matrix3 ptoz(-pPP.p3().unit(), Vector3(0,0,1));
boost.preMult(ptoz);
// the momenta in frane to W along z
FourMomentum pD = boost.transform(DD.decaying()[ix].momentum());
FourMomentum ppi2 = boost.transform(pi2.momentum());
FourMomentum ppim = boost.transform(pim.momentum());
FourMomentum pe = boost.transform(ep .momentum());
FourMomentum pnu = boost.transform(nue.momentum());
pRho = ppi2+ppim;
qq = pD-pRho;
LorentzTransform boostRho = LorentzTransform::mkFrameTransformFromBeta(pRho.betaVec());
Vector3 axisRho = boostRho.transform(ppim).p3().unit();
_h[imode+2]->fill(axisRho.dot(pRho.p3().unit()));
LorentzTransform boostW = LorentzTransform::mkFrameTransformFromBeta( qq.betaVec());
Vector3 axisE = boostW.transform(pe).p3().unit();
_h[imode+3]->fill(axisE.dot(qq.p3().unit()));
axisRho.setZ(0.);
axisE.setZ(0.);
double chi = atan2(axisE.cross(axisRho).dot(qq.p3().unit()), axisE.dot(axisRho));
_h[imode+4]->fill(chi);
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<10;++ix)
normalize(_h[ix]);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[10];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2019_I1694530);
}
|