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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief Omega decay asymmetries
class BABAR_2006_I719581 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2006_I719581);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(), "UFS" );
// Book histograms
book(_h_ctheta_xic ,1,1,1);
book(_h_ctheta_omegac,2,1,1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// loop over Xi_c0 baryons and Omega_c0 baryons
for(const Particle& baryon : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==4132 || Cuts::abspid==4332 )) {
int sign = baryon.pid()/baryon.abspid();
if(baryon.children().size()!=2) continue;
Particle baryon1,meson1;
if(baryon.abspid()==4132) {
if(baryon.children()[0].pid()==sign*3334 &&
baryon.children()[1].pid()==sign*321) {
baryon1 = baryon.children()[0];
meson1 = baryon.children()[1];
}
else if(baryon.children()[1].pid()==sign*3332 &&
baryon.children()[0].pid()==sign*321) {
baryon1 = baryon.children()[1];
meson1 = baryon.children()[0];
}
else
continue;
}
else {
if(baryon.children()[0].pid()==sign*3334 &&
baryon.children()[1].pid()==sign*211) {
baryon1 = baryon.children()[0];
meson1 = baryon.children()[1];
}
else if(baryon.children()[1].pid()==sign*3334 &&
baryon.children()[0].pid()==sign*211) {
baryon1 = baryon.children()[1];
meson1 = baryon.children()[0];
}
else
continue;
}
Particle baryon2,meson2;
if(baryon1.children()[0].pid()== sign*3122 &&
baryon1.children()[1].pid()==-sign*321) {
baryon2 = baryon1.children()[0];
meson2 = baryon1.children()[1];
}
else if(baryon1.children()[1].pid()== sign*3122 &&
baryon1.children()[0].pid()==-sign*321) {
baryon2 = baryon1.children()[1];
meson2 = baryon1.children()[0];
}
else
continue;
// first boost to the Xic/Omegac rest frame
LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(baryon.momentum().betaVec());
FourMomentum pbaryon1 = boost1.transform(baryon1.momentum());
FourMomentum pbaryon2 = boost1.transform(baryon2.momentum());
// to omega rest frame
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);
if(baryon.abspid()==4132)
_h_ctheta_xic->fill(cTheta,1.);
else
_h_ctheta_omegac->fill(cTheta,1.);
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_ctheta_xic);
normalize(_h_ctheta_omegac);
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_ctheta_xic,_h_ctheta_omegac;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(BABAR_2006_I719581);
}
|