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129 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief B0 -> psi(2S) K+ pi-
class BELLE_2013_I1239347 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2013_I1239347);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==511);
declare(ufs, "UFS");
DecayedParticles B0(ufs);
B0.addStable(100443);
declare(B0, "B0");
// histograms
for(unsigned int ix=0;ix<8;++ix)
book(_h_mass[ix],1,1,1+ix);
book(_h_mass[8],2,1,1);
for(unsigned int ix=0;ix<2;++ix)
book(_h_angle[ix],3,1,1+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 321,1},{-211,1}, { 100443,1}};
static const map<PdgId,unsigned int> & modeCC = { {-321,1},{ 211,1}, { 100443,1}};
DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
// loop over particles
for(unsigned int ix=0;ix<B0.decaying().size();++ix) {
int sign = 1;
if (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode)) {
sign=1;
}
else if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,modeCC)) {
sign=-1;
}
else
continue;
const Particle & Kp = B0.decayProducts()[ix].at( 321*sign)[0];
const Particle & pim = B0.decayProducts()[ix].at(-211*sign)[0];
const Particle & psi = B0.decayProducts()[ix].at( 100443 )[0];
double mKpi = (Kp .momentum()+pim.momentum()).mass();
double m2Psipi= (psi.momentum()+pim.momentum()).mass2();
if(m2Psipi<19.) _h_mass[0]->fill(sqr(mKpi));
else if(m2Psipi>=19. && m2Psipi<20.5) _h_mass[1]->fill(sqr(mKpi));
else if(m2Psipi>=20.5) _h_mass[2]->fill(sqr(mKpi));
if(mKpi<0.796) {
_h_mass[3]->fill(m2Psipi);
_h_mass[8]->fill(m2Psipi);
}
else if(mKpi>=0.796&&mKpi<0.996)
_h_mass[4]->fill(m2Psipi);
else if(mKpi>=0.996&&mKpi<1.332) {
_h_mass[5]->fill(m2Psipi);
_h_mass[8]->fill(m2Psipi);
}
else if(mKpi>=1.332&&mKpi<1.532)
_h_mass[6]->fill(m2Psipi);
else if(mKpi>=1.532) {
_h_mass[7]->fill(m2Psipi);
_h_mass[8]->fill(m2Psipi);
}
// need leptonic psi' decay for angular dists
if(psi.children().size()!=2|| psi.children()[0].pid()!=-psi.children()[1].pid() ||
(psi.children()[0].abspid()!=11 &&
psi.children()[0].abspid()!=11)) vetoEvent;
Particle lm = psi.children()[0];
Particle lp = psi.children()[1];
if(lm.pid()<0) swap(lm,lp);
LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(B0.decaying()[ix].momentum().betaVec());
FourMomentum pKstar = boost1.transform(Kp.momentum()+pim.momentum());
FourMomentum pPsi = boost1.transform(psi.momentum());
// trans vector in K* frame
LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pKstar.betaVec());
FourMomentum pKp = boost2.transform(boost1.transform(Kp.momentum()));
Vector3 axis1 = pKstar.p3().unit();
double cTheta1 = axis1.dot(pKp.p3().unit());
Vector3 trans1 = pKp.p3() - cTheta1*pKp.p3().mod()*axis1;
// leptons in psi' frame
LorentzTransform boost3 = LorentzTransform::mkFrameTransformFromBeta(pPsi.betaVec());
FourMomentum plm = boost3.transform(boost1.transform(lm.momentum()));
double cTheta2 = axis1.dot(plm.p3().unit());
Vector3 trans2 = plm.p3() - cTheta2*plm.p3().mod()*axis1;
_h_angle[0]->fill(cTheta2);
// angle between planes
double chi = atan2(trans1.cross(trans2).dot(axis1),trans1.dot(trans2));
_h_angle[1]->fill(chi);
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<9;++ix)
normalize(_h_mass[ix],1.,false);
normalize(_h_angle[0],1.,false);
normalize(_h_angle[1],1.,false);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_mass[9],_h_angle[2];
/// @}
};
RIVET_DECLARE_PLUGIN(BELLE_2013_I1239347);
}
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