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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief ARGUS D0, D+, D*+ production
class ARGUS_1991_I315059 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1991_I315059);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(UnstableParticles(), "UFS");
declare(Beam(), "Beams");
// Book histograms
book(_n_D0 , 1,1,1);
book(_n_Dp , 1,1,2);
book(_n_DStar, 1,1,3);
book(_h_x_D0 , 2,1,1);
book(_h_x_Dp , 3,1,1);
book(_h_x_DStar, 4,1,1);
book(_h_p_D0 , 5,1,1);
book(_h_p_Dp , 6,1,1);
book(_h_p_DStar, 7,1,1);
book(_c_cont, "/TMP/c_cont");
book(_c_ups , "/TMP/c_ups");
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Get beams and average beam momentum
const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
const double meanBeamMom = ( beams.first.p3().mod() +
beams.second.p3().mod() ) / 2.0;
MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
// Find the Upsilon(4S) among the unstables
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
Particles upsilons = ufs.particles(Cuts::pid==300553);
// Continuum
if (upsilons.empty()) {
_c_cont->fill();
MSG_DEBUG("No Upsilons found => continuum event");
for(const Particle &p : ufs.particles(Cuts::abspid==411 or Cuts::abspid==421 or Cuts::abspid==413)) {
double xp = p.p3().mod()/sqrt(sqr(meanBeamMom)+sqr(p.mass()));
if(p.abspid()==421) {
_h_x_D0->fill(xp);
_n_D0->fill(10.6);
}
else if(p.abspid()==411) {
_h_x_Dp->fill(xp);
_n_Dp->fill(10.6);
}
else if(p.abspid()==413) {
_h_x_DStar->fill(xp);
_n_DStar->fill(10.6);
}
}
}
// upsilon decay
else {
for (const Particle& ups : upsilons) {
_c_ups->fill();
Particles unstable;
// Find the decay products we want
findDecayProducts(ups, unstable);
// boost to rest frame (if required)
LorentzTransform cms_boost;
if (ups.p3().mod() > 1*MeV)
cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
for(const Particle& p : unstable) {
const FourMomentum p2 = cms_boost.transform(p.momentum());
double modp = p2.p3().mod();
if(p.abspid()==421) {
_h_p_D0->fill(modp);
}
else if(p.abspid()==411) {
_h_p_Dp->fill(modp);
}
else if(p.abspid()==413) {
_h_p_DStar->fill(modp);
}
}
}
}
}
/// 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 == 411 || id == 421) {
unstable.push_back(p);
}
else if (id == 413 ) {
unstable.push_back(p);
findDecayProducts(p, unstable);
}
else if(!p.children().empty())
findDecayProducts(p, unstable);
}
}
/// Normalise histograms etc., after the run
void finalize() {
// brs for the decays used (PDG 2018)
double brD0 = 0.0389;
double brDp = 0.0898;
double brDStar = 0.677;
if(_c_cont->numEntries()!=0) {
scale(_n_D0 , 1./sumOfWeights()*crossSection()/nanobarn);
scale(_n_Dp , 1./sumOfWeights()*crossSection()/nanobarn);
scale(_n_DStar , 1./sumOfWeights()*crossSection()/nanobarn);
scale(_h_x_D0 , brD0/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
scale(_h_x_Dp , brDp/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
scale(_h_x_DStar, brD0*brDStar/sumOfWeights()*crossSection()/nanobarn*sqr(sqrtS()));
}
if(_c_ups->numEntries()!=0) {
scale(_h_p_D0 , 1e3*0.5*brD0/ *_c_ups);
scale(_h_p_Dp , 1e3*0.5*brDp/ *_c_ups);
scale(_h_p_DStar, 1e3*0.5*brD0*brDStar/ *_c_ups);
}
}
//@}
/// @name Histograms
//@{
Histo1DPtr _n_D0,_n_Dp,_n_DStar;
Histo1DPtr _h_x_D0,_h_x_Dp,_h_x_DStar;
Histo1DPtr _h_p_D0,_h_p_Dp,_h_p_DStar;
CounterPtr _c_cont, _c_ups;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(ARGUS_1991_I315059);
}
|