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120 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief q^2 in D_s+ -> K0 e+ nu_e and ->K*0 e+ nu_e distributions
class BESIII_2019_I1702549 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2019_I1702549);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::pid==431);
declare(ufs, "UFS");
DecayedParticles DS(ufs);
DS.addStable(PID::PI0);
DS.addStable(PID::K0S);
DS.addStable(PID::ETA);
DS.addStable(PID::ETAPRIME);
declare(DS, "DS");
// Book histograms
book(_h_q2, 1, 1, 1);
book(_nD,"/TMP/nD");
for(unsigned int ix=0;ix<5;++ix)
book(_h_Kstar[ix],1,1,3+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode1 = { { 310,1}, {-11,1}, { 12,1}};
static const map<PdgId,unsigned int> & mode2 = { { 130,1}, {-11,1}, { 12,1}};
static const map<PdgId,unsigned int> & mode3 = { { 311,1}, {-11,1}, { 12,1}};
static const map<PdgId,unsigned int> & mode4 = { { 321,1}, {-211,1}, {-11,1}, { 12,1}};
DecayedParticles DS = apply<DecayedParticles>(event, "DS");
// loop over particles
for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
_nD->fill();
if(DS.modeMatches(ix,3,mode1)) {
_h_q2->fill((DS.decaying()[ix].momentum()-DS.decayProducts()[ix].at(310)[0].momentum()).mass2());
}
else if(DS.modeMatches(ix,3,mode2)) {
_h_q2->fill((DS.decaying()[ix].momentum()-DS.decayProducts()[ix].at(130)[0].momentum()).mass2());
}
else if(DS.modeMatches(ix,3,mode3)) {
_h_q2->fill((DS.decaying()[ix].momentum()-DS.decayProducts()[ix].at(311)[0].momentum()).mass2());
}
else if(DS.modeMatches(ix,4,mode4)) {
const Particle & Kp = DS.decayProducts()[ix].at( 321)[0];
const Particle & pim= DS.decayProducts()[ix].at(-211)[0];
const Particle & ep = DS.decayProducts()[ix].at(-11)[0];
const Particle & nue= DS.decayProducts()[ix].at( 12)[0];
FourMomentum pKstar = Kp.momentum()+pim.momentum();
_h_Kstar[0]->fill(pKstar.mass());
FourMomentum qq = DS.decaying()[ix].momentum()-pKstar;
_h_Kstar[1]->fill(qq.mass2());
// boost momenta to Ds rest frame
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(DS.decaying()[ix].momentum().betaVec());
FourMomentum pKS = boost.transform(pKstar);
Matrix3 ptoz(-pKS.p3().unit(), Vector3(0,0,1));
boost.preMult(ptoz);
// the momenta in frane to W along z
FourMomentum pD = boost.transform(DS.decaying()[ix].momentum());
FourMomentum pK = boost.transform(Kp .momentum());
FourMomentum ppi = boost.transform(pim.momentum());
FourMomentum pe = boost.transform(ep .momentum());
FourMomentum pnu = boost.transform(nue.momentum());
pKstar = pK+ppi;
qq = pD-pKstar;
LorentzTransform boostK = LorentzTransform::mkFrameTransformFromBeta(pKstar.betaVec());
Vector3 axisK = boostK.transform(pK).p3().unit();
_h_Kstar[3]->fill(axisK.dot(pKstar.p3().unit()));
LorentzTransform boostW = LorentzTransform::mkFrameTransformFromBeta( qq.betaVec());
Vector3 axisE = boostW.transform(pe).p3().unit();
_h_Kstar[2]->fill(axisE.dot(qq.p3().unit()));
axisK.setZ(0.);
axisE.setZ(0.);
double chi = atan2(axisE.cross(axisK).dot(qq.p3().unit()), axisE.dot(axisK));
_h_Kstar[4]->fill(chi);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
// normalise to width in inverse ns
scale(_h_q2, 1./0.504e-3/ *_nD);
for(unsigned int ix=0;ix<5;++ix)
normalize(_h_Kstar[ix]);
}
///@}
/// @name Histograms
///@{
Histo1DPtr _h_q2;
Histo1DPtr _h_Kstar[5];
CounterPtr _nD;
///@}
};
RIVET_DECLARE_PLUGIN(BESIII_2019_I1702549);
}
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