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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief D_1 and D_2 decay distributions
class BABAR_2010_I867611 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2010_I867611);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(), "UFS");
// Book histograms
book(_h_D1_ctheta, 1,1,1);
book(_h_D2_ctheta, 1,1,2);
book(_h_D02S_ctheta, 1,1,3);
book(_h_DStar02S_ctheta, 1,1,4);
book(_h_D3_ctheta, 1,1,5);
}
/// Recursively walk the decay tree to find decay products of @a p
void findDecayProducts(Particle mother, Particles & dstar, Particles & d0, Particles & pi,unsigned int & ncount) {
for(const Particle & p: mother.children()) {
if(p.abspid()==413)
dstar.push_back(p);
else if(p.abspid()==421)
d0.push_back(p);
else if(p.abspid()==211)
pi.push_back(p);
ncount +=1;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for(const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==425 || Cuts::abspid==10423 ||
Cuts::abspid==100421 || Cuts::abspid==100423 ||
Cuts::abspid==427)) {
// decay products
Particles dstar,d0,pi;
unsigned int ncount=0;
findDecayProducts(p,dstar,d0, pi,ncount);
if(ncount!=2 || dstar.size()!=1 || pi.size()!=1 || d0.size()!=0 ) continue;
if(dstar[0].pid()/p.pid()<0) continue;
Particle p2 = dstar[0];
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p2.momentum().betaVec());
Vector3 d1 = boost.transform(pi[0].momentum()).p3().unit();
ncount=0;
dstar.clear();
d0.clear();
pi.clear();
findDecayProducts(p2,dstar,d0, pi,ncount);
if(ncount!=2 || dstar.size()!=0 || pi.size()!=1 || d0.size()!=1 ) continue;
if(pi[0].pid()/p2.pid()<0) continue;
Vector3 d2 = boost.transform(pi[0].momentum()).p3().unit();
double cTheta = d1.dot(d2);
// decay angles
if(p.abspid()==425)
_h_D2_ctheta->fill(cTheta);
else if(p.abspid()==10423)
_h_D1_ctheta->fill(cTheta);
else if(p.abspid()==100421)
_h_D02S_ctheta->fill(cTheta);
else if(p.abspid()==100423)
_h_DStar02S_ctheta->fill(cTheta);
else if(p.abspid()==427)
_h_D3_ctheta->fill(cTheta);
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_D1_ctheta);
normalize(_h_D2_ctheta);
normalize(_h_D02S_ctheta);
normalize(_h_DStar02S_ctheta);
normalize(_h_D3_ctheta);
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_D1_ctheta,_h_D2_ctheta,_h_D02S_ctheta;
Histo1DPtr _h_DStar02S_ctheta,_h_D3_ctheta;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(BABAR_2010_I867611);
}
|