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127 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief Lambda in Upsilon(1S) decay and nearby continuum
class MD1_1994_I362599 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MD1_1994_I362599);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// projections
declare(UnstableParticles(), "UFS");
// histos
book(_weightSum_cont,"TMP/weightSumcont");
book(_weightSum_Ups1,"TMP/weightSumUps1");
book(_h_spect,1,1,1);
for (unsigned int ix=0; ix<2; ++ix) {
for (unsigned int iy=0; iy<2; ++iy) {
book(_mult[ix][iy],"/TMP/MULT_" +toString(ix) + "_" +toString(iy));
}
}
}
/// Recursively walk the decay tree to find decay products of @a p
void findDecayProducts(Particle mother, Particles& unstable) {
for (const Particle & p: mother.children()) {
const int id = p.abspid();
if (id==PID::LAMBDA || id==PID::XIMINUS) unstable.push_back(p);
if (!p.children().empty()) findDecayProducts(p, unstable);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Find the upsilons
// First in unstable final state
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
Particles upsilons = ufs.particles(Cuts::pid==553);
// continuum
if (upsilons.empty()) {
_weightSum_cont->fill();
// Unstable particles
for (const Particle& p : ufs.particles(Cuts::abspid==PID::LAMBDA)) {
(void)p; // to suppress "unused variable" warning
_mult[1][0]->fill();
}
}
else {
for (const Particle& ups : upsilons) {
_weightSum_Ups1->fill();
Particles unstable;
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
// Find the decay products we want
findDecayProducts(ups,unstable);
for(const Particle & p : unstable) {
int id = p.abspid();
if(id==PID::LAMBDA) {
double xp = 2.*boost.transform(p.momentum()).p3().mod()/ups.mass();
_h_spect->fill(xp);
_mult[0][0]->fill();
}
else if(id==PID::XIMINUS) {
_mult[0][1]->fill();
}
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
if (_weightSum_Ups1->val() > 0.) {
scale(_h_spect,1./ *_weightSum_Ups1);
for(unsigned int iy=0;iy<2;++iy) {
Scatter2DPtr scatter;
book(scatter,2+iy*2, 1, 1, true);
if(_weightSum_Ups1->val() <= 0.) {
scatter->point(0).setY(0.,0.);
}
else {
scale(_mult[0][iy],1./ *_weightSum_Ups1);
scatter->point(0).setY(_mult[0][iy]->val(),_mult[0][iy]->err());
}
}
}
if (_weightSum_cont->val() > 0.) {
scale(_mult[1][0],1./ *_weightSum_cont);
for(unsigned int ix=0;ix<2;++ix) {
Scatter2DPtr scatter;
book(scatter,3, 1, 1+ix, true);
if(inRange(sqrtS(),7.2,10.) && ix==1)
scatter->point(0).setY(_mult[1][0]->val(),_mult[1][0]->err());
else if(inRange(sqrtS(),7.2,9.4) && ix==0)
scatter->point(0).setY(_mult[1][0]->val(),_mult[1][0]->err());
}
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_spect;
CounterPtr _weightSum_cont,_weightSum_Ups1;
CounterPtr _mult[2][2];
/// @}
};
RIVET_DECLARE_PLUGIN(MD1_1994_I362599);
}
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