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 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief B- > D+ pi-pi-
class BABAR_2009_I810694 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2009_I810694);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==521);
declare(ufs, "UFS");
DecayedParticles BP(ufs);
BP.addStable( 411);
BP.addStable(-411);
declare(BP, "BP");
// histograms
for(unsigned int ix=0;ix<3;++ix) {
if(ix<2) book(_h_angle[ix],2,1,1+ix);
book(_h_mass[ix],1,1,1+ix);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { -411,1},{ 211,2}};
static const map<PdgId,unsigned int> & modeCC = { { 411,1},{-211,2}};
DecayedParticles BP = apply<DecayedParticles>(event, "BP");
// loop over particles
for(unsigned int ix=0;ix<BP.decaying().size();++ix) {
int sign=1;
if (BP.modeMatches(ix,3,mode )) sign= 1;
else if (BP.modeMatches(ix,3,modeCC)) sign=-1;
else continue;
const Particle & Dp = BP.decayProducts()[ix].at(-sign*411)[0];
const Particles & pim = BP.decayProducts()[ix].at( sign*211);
_h_mass[2]->fill((pim[0].momentum()+pim[1].momentum()).mass2());
// boost to B rest frame
LorentzTransform boost =
LorentzTransform::mkFrameTransformFromBeta(BP.decaying()[ix]. momentum().betaVec());
FourMomentum pD = boost.transform(Dp.momentum());
FourMomentum ppi[2] = {boost.transform(pim[0].momentum()),boost.transform(pim[1].momentum())};
double m2Dpi[2];
for(unsigned int ix=0;ix<2;++ix) {
m2Dpi[ix] = (pim[ix].momentum()+Dp.momentum()).mass2();
if( (m2Dpi[ix]>4.5 && m2Dpi[ix]<5.5) ||
(m2Dpi[ix]>5.9 && m2Dpi[ix]<6.2) ) {
FourMomentum pDpi = pD+pim[ix];
LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pDpi.betaVec());
Vector3 axis1 = boost2.transform(ppi[ix]).p3().unit();
Vector3 axis2 = (ix==0 ? ppi[1] : ppi[0]).p3().unit();
double cTheta = axis1.dot(axis2);
if(m2Dpi[ix]<5.5)
_h_angle[0]->fill(cTheta);
else
_h_angle[1]->fill(cTheta);
}
}
if(m2Dpi[0]>m2Dpi[1]) {
_h_mass[1]->fill(m2Dpi[0]);
_h_mass[0]->fill(m2Dpi[1]);
}
else {
_h_mass[0]->fill(m2Dpi[0]);
_h_mass[1]->fill(m2Dpi[1]);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<3;++ix) {
if(ix<2) normalize(_h_angle[ix],1.,false);
normalize(_h_mass[ix],1.,false);
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_mass[3],_h_angle[2];
/// @}
};
RIVET_DECLARE_PLUGIN(BABAR_2009_I810694);
}
|