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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief J/Psi and Psi(2S) spectra at the Upsilon(4S)
class CLEOII_2002_I606309 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_2002_I606309);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
// projections
declare(UnstableParticles(), "UFS");
//histograms
book(_weightSum,"/TMP/weightSum");
book(_h_Jpsi ,3,1,1);
book(_h_Psi_prime ,3,1,2);
book(_h_cTheta_Jpsi ,4,1,1);
book(_h_cTheta_Psi_prime,4,1,2);
double bins[4]={0.,.8,1.4,2.};
for(unsigned int ix=0;ix<3;++ix) {
Histo1DPtr temp;
std::ostringstream title;
title << "/TMP/ctheta_" << ix;
book(temp,title.str(),20,-1.,1.);
_h2_cTheta_Jpsi.add(bins[ix],bins[ix+1],temp);
}
}
void findDecayProducts(Particle parent, Particles & charm) {
for (const Particle & p :parent.children()) {
if (p.pid()==443) {
charm.push_back(p);
continue;
}
else if (p.pid()==100443) {
charm.push_back(p);
}
if(!p.children().empty())
findDecayProducts(p,charm);
}
}
void findLeptons(const Particle & mother,
unsigned int & nstable,
Particles& lp, Particles& lm) {
for(const Particle & p : mother.children()) {
int id = p.pid();
if ( id == 11 || id == 13 ) {
lm.push_back(p);
++nstable;
}
else if (id == -11 || id==-13) {
lp.push_back(p);
++nstable;
}
else if ( !p.children().empty() ) {
findLeptons(p,nstable,lp,lm);
}
else
++nstable;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
for (const Particle& p : ufs.particles(Cuts::pid==300553)) {
_weightSum->fill();
const LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
Particles charm;
findDecayProducts(p,charm);
for(const Particle & pp : charm) {
FourMomentum pcm = boost.transform(pp.momentum());
unsigned int nstable = 0;
Particles lp, lm;
findLeptons(pp,nstable,lp,lm);
double cTheta(0.);
bool foundLeptons(false);
if(nstable==2&&lp.size()==1&&lm.size()==1) {
foundLeptons=true;
FourMomentum pl = boost.transform(lm[0].momentum());
const LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pcm.betaVec());
pl = boost2.transform(pl);
cTheta = pl.p3().unit().dot(pcm.p3().unit());
}
if(pp.pid()==443) {
_h_Jpsi->fill(pcm.p3().mod());
if(foundLeptons) {
_h_cTheta_Jpsi->fill(cTheta);
_h2_cTheta_Jpsi.fill(pcm.p3().mod(),cTheta);
}
}
else {
_h_Psi_prime->fill(pcm.p3().mod());
if(foundLeptons) {
_h_cTheta_Psi_prime->fill(cTheta);
}
}
}
}
}
pair<double,pair<double,double> > calcAlpha(Histo1DPtr hist) {
if(hist->numEntries()==0.) return make_pair(0.,make_pair(0.,0.));
double d = 3./(pow(hist->xMax(),3)-pow(hist->xMin(),3));
double c = 3.*(hist->xMax()-hist->xMin())/(pow(hist->xMax(),3)-pow(hist->xMin(),3));
double sum1(0.),sum2(0.),sum3(0.),sum4(0.),sum5(0.);
for (auto bin : hist->bins() ) {
double Oi = bin.area();
if(Oi==0.) continue;
double a = d*(bin.xMax() - bin.xMin());
double b = d/3.*(pow(bin.xMax(),3) - pow(bin.xMin(),3));
double Ei = bin.areaErr();
sum1 += a*Oi/sqr(Ei);
sum2 += b*Oi/sqr(Ei);
sum3 += sqr(a)/sqr(Ei);
sum4 += sqr(b)/sqr(Ei);
sum5 += a*b/sqr(Ei);
}
// calculate alpha
double alpha = (-c*sum1 + sqr(c)*sum2 + sum3 - c*sum5)/(sum1 - c*sum2 + c*sum4 - sum5);
// and error
double cc = -pow((sum3 + sqr(c)*sum4 - 2*c*sum5),3);
double bb = -2*sqr(sum3 + sqr(c)*sum4 - 2*c*sum5)*(sum1 - c*sum2 + c*sum4 - sum5);
double aa = sqr(sum1 - c*sum2 + c*sum4 - sum5)*(-sum3 - sqr(c)*sum4 + sqr(sum1 - c*sum2 + c*sum4 - sum5) + 2*c*sum5);
double dis = sqr(bb)-4.*aa*cc;
if(dis>0.) {
dis = sqrt(dis);
return make_pair(alpha,make_pair(0.5*(-bb+dis)/aa,-0.5*(-bb-dis)/aa));
}
else {
return make_pair(alpha,make_pair(0.,0.));
}
}
/// Normalise histograms etc., after the run
void finalize() {
if(_weightSum->val()==0.) return;
scale(_h_Jpsi , 50./ *_weightSum);
scale(_h_Psi_prime, 50./ *_weightSum);
// polarization J/psi
normalize(_h_cTheta_Jpsi);
pair<double,pair<double,double> > alpha = calcAlpha(_h_cTheta_Jpsi);
Scatter2DPtr _h_alpha;
book(_h_alpha,1,1,1);
_h_alpha->addPoint(1., alpha.first, make_pair(1.,1.),
make_pair(alpha.second.first,alpha.second.second) );
// polarization psi(2S)
normalize(_h_cTheta_Psi_prime);
alpha = calcAlpha(_h_cTheta_Psi_prime);
book(_h_alpha,1,1,2);
_h_alpha->addPoint(0.8, alpha.first, make_pair(0.8,0.8),
make_pair(alpha.second.first,alpha.second.second) );
// J/psi as function of momentum
double bins[4]={0.,.8,1.4,2.};
book(_h_alpha,2,1,1);
for(unsigned int ix=0;ix<3;++ix) {
normalize(_h2_cTheta_Jpsi.histos()[ix]);
double cen = 0.5*(bins[ix+1]+bins[ix]);
double wid = 0.5*(bins[ix+1]-bins[ix]);
alpha = calcAlpha(_h2_cTheta_Jpsi.histos()[ix]);
_h_alpha->addPoint(cen, alpha.first, make_pair(wid,wid),
make_pair(alpha.second.first,alpha.second.second) );
}
}
///@}
/// @name Histograms
///@{
// count of weights
CounterPtr _weightSum;
// histograms
Histo1DPtr _h_Jpsi,_h_Psi_prime;
Histo1DPtr _h_cTheta_Jpsi,_h_cTheta_Psi_prime;
BinnedHistogram _h2_cTheta_Jpsi;
///@}
};
RIVET_DECLARE_PLUGIN(CLEOII_2002_I606309);
}
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