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110 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief D+ -> K- pi+ pi+
class CLEOC_2008_I780363 : public Analysis {
public:
/// Constructor
DEFAULT_RIVET_ANALYSIS_CTOR(CLEOC_2008_I780363);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==411);
declare(ufs, "UFS");
DecayedParticles DP(ufs);
DP.addStable(PID::PI0);
DP.addStable(PID::K0S);
DP.addStable(PID::ETA);
DP.addStable(PID::ETAPRIME);
declare(DP, "DP");
// histos
book(_h_Kpiall,1,1,1);
book(_h_pipi ,1,2,1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// parameters from the efficiency function, table 1 in paper
static const double E1 = -0.0153;
static const double E2 = -0.030;
static const double E3 = 0.162;
static const double Exy = -0.053;
static const double Exyn = 0.673;
// static const double Eth[3] = {4.25,4.25,2.907};
static const map<PdgId,unsigned int> & mode = { { 211,2},{-321,1}};
static const map<PdgId,unsigned int> & modeCC = { {-211,2},{ 321,1}};
DecayedParticles DP = apply<DecayedParticles>(event, "DP");
// loop over particles
for(unsigned int ix=0;ix<DP.decaying().size();++ix) {
int sign = 1;
if (DP.decaying()[ix].pid()>0 && DP.modeMatches(ix,3,mode)) {
sign=1;
}
else if (DP.decaying()[ix].pid()<0 && DP.modeMatches(ix,3,modeCC)) {
sign=-1;
}
else
continue;
const Particle & Km = DP.decayProducts()[ix].at(-sign*321)[0];
const Particles & pip= DP.decayProducts()[ix].at( sign*211);
// kinematic variables
double x[3] = {(Km .momentum() +pip[0].momentum()).mass2(),
(Km .momentum() +pip[1].momentum()).mass2(),
(pip[0].momentum()+pip[1].momentum()).mass2()};
if(x[1]<x[0]) swap(x[0],x[1]);
// calculate the efficiency, eqns 6,7 from paper
// double xmax[3] = {sqr(meson.mass()-pip[0].mass()),
// sqr(meson.mass()-pip[0].mass()),
// sqr(meson.mass()-Km .mass())};
double xh = x[0]-1.5,yh=x[1]-1.5;
double eff = (1.+E1*(xh+yh)+E2*(sqr(xh)+sqr(yh))+E3*(pow(xh,3)+pow(yh,3))
+Exy*xh*yh+Exyn*xh*yh*(xh+yh));
// double T=1.;
// for(unsigned int ix=2;ix<3;++ix) {
// double arg = Eth[ix]*abs(x[ix]-xmax[ix]);
// if(arg<0.5*M_PI) T *=sin(arg);
// }
// eff *=T;
// fill plots
_h_Kpiall->fill( x[0],eff);
_h_Kpiall->fill( x[1],eff);
_h_pipi ->fill( x[2],eff);
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_Kpiall);
normalize(_h_pipi );
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_Kpiall, _h_pipi;
//@}
};
RIVET_DECLARE_PLUGIN(CLEOC_2008_I780363);
}
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