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123 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief D0 -> KS) K+/- pi-/+
class LHCB_2016_I1394391 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2016_I1394391);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==421);
declare(ufs, "UFS");
DecayedParticles D0(ufs);
D0.addStable(PID::PI0);
D0.addStable(PID::K0S);
D0.addStable(PID::ETA);
D0.addStable(PID::ETAPRIME);
declare(D0, "D0");
// histograms
book(_h_Kmpip,1,1,1);
book(_h_K0pip,1,1,2);
book(_h_K0Km ,1,1,3);
book(_h_Kppim,2,1,1);
book(_h_K0pim,2,1,2);
book(_h_K0Kp ,2,1,3);
book(_dalitz [0],"dalitz_1",50,0.3,2.0,50,0.3,2.);
book(_dalitz [1],"dalitz_2",50,0.3,2.0,50,0.3,2.);
}
double efficiency(const double & x, const double &y) {
double X=x-2., Y=y-1.;
static const double E0 = 5.8096, Ex = -3.645, Ey = -3.174, Ex2= 0.831,
Exy = 2.131, Ey2 = 4.43, Ex3 = -0.427, Ex2y = 2.65, Exy2 = 1.50, Ey3 = -3.92;
return E0 + Ex*X + Ey*Y + Ex2*sqr(X) + Ey2*sqr(Y) + Exy*X*Y +
Ex3*pow(X,3) + Ex2y*sqr(X)*Y + Exy2*X*sqr(Y) + Ey3*pow(Y,3);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 321,1},{-211,1}, { 310,1}};
static const map<PdgId,unsigned int> & modeCC = { {-321,1},{ 211,1}, { 310,1}};
DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
// loop over particles
for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
if( !D0.modeMatches(ix,3,mode ) &&
!D0.modeMatches(ix,3,modeCC) ) continue;
const Particles & K0 = D0.decayProducts()[ix].at(310);
int sign = D0.decaying()[ix].pid()/421;
const Particles & pip= D0.decayProducts()[ix].find( sign*211) == D0.decayProducts()[ix].end() ?
Particles() : D0.decayProducts()[ix].at( sign*211);
const Particles & pim= D0.decayProducts()[ix].find(-sign*211) == D0.decayProducts()[ix].end() ?
Particles() : D0.decayProducts()[ix].at(-sign*211);
const Particles & Kp = D0.decayProducts()[ix].find( sign*321) == D0.decayProducts()[ix].end() ?
Particles() : D0.decayProducts()[ix].at( sign*321);
const Particles & Km = D0.decayProducts()[ix].find(-sign*321) == D0.decayProducts()[ix].end() ?
Particles() : D0.decayProducts()[ix].at(-sign*321);
// K0S K- pi+
if( Km.size()==1 && pip.size()==1) {
double mK0pip = (K0[0].momentum()+pip[0].momentum() ).mass2();
double mKmpip = (Km[0].momentum()+pip[0].momentum() ).mass2();
double mKK = (K0[0].momentum()+Km [0].momentum() ).mass2();
double eff = efficiency(mKK,mK0pip);
_h_K0Km ->fill(mKK ,eff);
_h_K0pip->fill(mK0pip,eff);
_h_Kmpip->fill(mKmpip,eff);
_dalitz[0]->fill(mKmpip,mK0pip);
}
// K0S K+ pi-
else if( Kp.size()==1 && pim.size()==1) {
double mK0pim = (K0[0].momentum()+pim[0].momentum() ).mass2();
double mKppim = (Kp[0].momentum()+pim[0].momentum() ).mass2();
double mKK = (K0[0].momentum()+Kp [0].momentum() ).mass2();
double eff = efficiency(mKK,mK0pim);
_h_K0Kp ->fill(mKK ,eff);
_h_K0pim->fill(mK0pim,eff);
_h_Kppim->fill(mKppim,eff);
_dalitz[1]->fill(mKppim,mK0pim);
}
}
}
/// Normalise histograms etc., after the runbook
void finalize() {
normalize(_h_Kmpip);
normalize(_h_K0pip);
normalize(_h_K0Km );
normalize(_h_Kppim);
normalize(_h_K0pim);
normalize(_h_K0Kp );
normalize(_dalitz [0]);
normalize(_dalitz [1]);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_Kmpip, _h_K0pip, _h_K0Km;
Histo1DPtr _h_Kppim, _h_K0pim, _h_K0Kp;
Histo2DPtr _dalitz[2];
/// @}
};
RIVET_DECLARE_PLUGIN(LHCB_2016_I1394391);
}
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