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105 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief Lambda_c+ -> Lambda Kbar0 K+
class BABAR_2006_I722213 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2006_I722213);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==4122);
declare(ufs, "UFS");
DecayedParticles LAMBDAC(ufs);
LAMBDAC.addStable(PID::PI0);
LAMBDAC.addStable(PID::K0S);
LAMBDAC.addStable(PID::ETA);
LAMBDAC.addStable(PID::LAMBDA);
LAMBDAC.addStable(-PID::LAMBDA);
declare(LAMBDAC, "LAMBDAC");
// histograms
for(unsigned int ix=0;ix<3;++ix)
book(_h_mass[ix],1,1,1+ix);
for(unsigned int ix=0;ix<2;++ix)
book(_h_ctheta[ix],2,1,1+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { PID::LAMBDA,1}, { 321,1}, { 310,1}};
static const map<PdgId,unsigned int> & modeCC = { {-PID::LAMBDA,1}, {-321,1}, { 310,1}};
DecayedParticles LAMBDAC = apply<DecayedParticles>(event, "LAMBDAC");
// loop over particles
for(unsigned int ix=0;ix<LAMBDAC.decaying().size();++ix) {
int sign = 1;
if (LAMBDAC.decaying()[ix].pid()>0 && LAMBDAC.modeMatches(ix,3,mode)) {
sign=1;
}
else if (LAMBDAC.decaying()[ix].pid()<0 && LAMBDAC.modeMatches(ix,3,modeCC)) {
sign=-1;
}
else
continue;
const Particle & lam = LAMBDAC.decayProducts()[ix].at( sign*PID::LAMBDA)[0];
const Particle & K0 = LAMBDAC.decayProducts()[ix].at( 310)[0];
const Particle & Kp = LAMBDAC.decayProducts()[ix].at( sign*321)[0];
double mLamK = (lam.momentum()+K0.momentum()).mass();
_h_mass[0]->fill(mLamK);
_h_mass[1]->fill((Kp .momentum()+K0.momentum()).mass()-Kp.mass()-K0.mass());
_h_mass[2]->fill((lam.momentum()+Kp.momentum()).mass()-Kp.mass()-lam.mass());
// take Xi(1690) to be any resonance in mass region
if(mLamK<1.6725 || mLamK>1.6975) continue;
if(LAMBDAC.decaying()[ix].children().size()!=2) continue;
if(LAMBDAC.decaying()[ix].children()[0].abspid()!=321 &&
LAMBDAC.decaying()[ix].children()[1].abspid()!=321) continue;
LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(LAMBDAC.decaying()[ix].momentum().betaVec());
FourMomentum pbaryon1 = boost1.transform(LAMBDAC.decaying()[ix].momentum());
FourMomentum pbaryon2 = boost1.transform(lam.momentum());
LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pbaryon1.betaVec());
Vector3 axis = pbaryon1.p3().unit();
FourMomentum pp = boost2.transform(pbaryon2);
// calculate angle
double cTheta = pp.p3().unit().dot(axis);
_h_ctheta[0]->fill(cTheta);
_h_ctheta[1]->fill(cTheta);
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<3;++ix)
normalize(_h_mass [ix]);
for(unsigned int ix=0;ix<2;++ix)
normalize(_h_ctheta[ix]);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_mass [3];
Histo1DPtr _h_ctheta[2];
/// @}
};
RIVET_DECLARE_PLUGIN(BABAR_2006_I722213);
}
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