Rivet analyses
γγ → K*0K̄*0 between 1.6 and 3.5 GeV
Experiment: ARGUS (DORIS)
Inspire ID: 248680
Status: VALIDATED
Authors: - Peter Richardson
References: - Eur.Phys.J.C 16 (2000) 435-444
Beams: 22 22
Beam energies: (0.8, 0.8); (0.9, 0.9); (0.9, 0.9); (0.9, 0.9); (1.0, 1.0); (1.0, 1.0); (1.1, 1.1); (1.1, 1.1); (1.1, 1.1); (1.2, 1.2); (1.2, 1.2); (1.3, 1.3); (1.3, 1.3); (1.3, 1.3); (1.4, 1.4); (1.4, 1.4); (1.5, 1.5); (1.5, 1.5); (1.5, 1.5); (1.6, 1.6); (1.6, 1.6); (1.7, 1.7)GeV
Run details: - gamma gamma to hadrons, K0S and pi0 mesons must be set stable
Measurement of the differential cross section for γγ → K*0K̄*0 for 1.6GeV < W < 3.5GeV. The cross section is measured as a function of the centre-of-mass energy of the photonic collision using the K+K−π+π− final state.
Source
code:ARGUS_1987_I248680.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief gamma gamma -> K*0K*0
class ARGUS_1987_I248680 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1987_I248680);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(FinalState(), "FS");
declare(UnstableParticles(), "UFS");
// book histos
for (size_t ih=0; ih<5; ++ih) {
book(_est[ih], 5, 1, ih+1);
book(_xsec[ih], "_aux_xsec_"+toString(ih), _est[ih].binning().edges<0>());
}
for (double eVal : allowedEnergies()) {
const string en = toString(round(eVal/MeV));
if (isCompatibleWithSqrtS(eVal)) _sqs = en;
for (size_t ix=0; ix<9; ++ix) {
book(_nMeson[en+toString(ix)],"TMP/nMeson_"+en+"_"+toString(ix+1));
}
}
raiseBeamErrorIf(_sqs.empty());
}
void findChildren(const Particle& p, map<long,int>& nRes, int& ncount) const {
for (const Particle& child : p.children()) {
if (child.children().empty()) {
nRes[child.pid()]-=1;
--ncount;
}
else {
findChildren(child,nRes,ncount);
}
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const FinalState& fs = apply<FinalState>(event, "FS");
// find the final-state particles
map<long,int> nCount;
int ntotal(0);
for (const Particle& p : fs.particles()) {
nCount[p.pid()] += 1;
++ntotal;
}
// find any K* mesons
int ires=-1;
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
Particles Kstar=ufs.particles(Cuts::abspid==313);
for (size_t ix=0; ix<Kstar.size(); ++ix) {
if (Kstar[ix].children().empty()) continue;
map<long,int> nRes=nCount;
int ncount = ntotal;
findChildren(Kstar[ix],nRes,ncount);
bool matched=false;
// K*K*
for (size_t iy=ix+1; iy<Kstar.size(); ++iy) {
if (Kstar[iy].children().empty()) continue;
if (Kstar[ix].pid()!=-Kstar[iy].pid()) continue;
map<long,int> nRes2=nRes;
int ncount2 = ncount;
findChildren(Kstar[iy],nRes2,ncount2);
if (ncount2 !=0 ) continue;
matched = true;
for (const auto& val : nRes2) {
if (val.second!=0) {
matched = false;
break;
}
}
if (matched) {
break;
}
}
if (matched) {
_nMeson[_sqs+"1"s]->fill();
ires=7;
break;
}
int sign = Kstar[ix].pid()/Kstar[ix].abspid();
// three body intermediate states
if (ncount==2) {
// K*0 K- pi+ +ccd
matched=true;
for (const auto& val : nRes) {
if (val.first==sign*211 || val.first==-sign*321) {
if (val.second!=1) {
matched = false;
break;
}
}
else {
if (val.second!=0) {
matched = false;
break;
}
}
}
if (matched) {
_nMeson[_sqs+"2"s]->fill();
ires=6;
break;
}
}
}
// look for phi modes
for (const Particle& p : ufs.particles(Cuts::pid==PID::PHI)) {
if (p.children().empty()) continue;
map<long,int> nRes=nCount;
int ncount = ntotal;
findChildren(p,nRes,ncount);
if (ncount==2) {
bool matched=true;
for (const auto& val : nRes) {
if (abs(val.first)==211) {
if (val.second!=1) {
matched = false;
break;
}
}
else {
if (val.second!=0) {
matched = false;
break;
}
}
}
if (matched) {
ires=8;
break;
}
}
}
// 4 meson modes
if (ntotal==4 &&
nCount[PID::KPLUS ]==1 && nCount[PID::KMINUS ]==1 &&
nCount[PID::PIPLUS]==1 && nCount[PID::PIMINUS]==1 ) {
_nMeson[_sqs+"0"s]->fill();
_nMeson[_sqs+"4"s]->fill();
_xsec[0]->fill(sqrtS()/GeV);
if (ires<0) {
_nMeson[_sqs+"3"s]->fill();
_nMeson[_sqs+"5"s]->fill();
_xsec[1]->fill(sqrtS()/GeV);
}
else {
_nMeson[_sqs+toString(ires)]->fill();
if (ires > 3) _xsec[ires-4]->fill(sqrtS()/GeV);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
const double sf = crossSection()/nanobarn/sumOfWeights();
scale(_nMeson, sf);
scale(_xsec, sf);
for (size_t ih=0; ih<4; ++ih) {
barchart(_xsec[ih], _est[ih]);
}
// loop over tables in paper
for (size_t ih=1; ih<5; ++ih) {
for (size_t iy=1; iy<2; ++iy) {
string iloc = toString(ih+iy-2);
BinnedEstimatePtr<string> mult;
book(mult, ih, 1, iy);
for (auto& b : mult->bins()) {
const double eVal = stod(b.xEdge());
const string en = toString(round(eVal/MeV));
b.set(_nMeson[en+iloc]->val(), _nMeson[en+iloc]->err());
}
}
}
}
/// @}
/// @name Histograms
/// @{
map<string,CounterPtr> _nMeson;
Histo1DPtr _xsec[5];
Estimate1DPtr _est[5];
string _sqs = "";
/// @}
};
RIVET_DECLARE_PLUGIN(ARGUS_1987_I248680);
}