Rivet analyses
Cross section for e+e− → K+K−3π0, KS0K±π∓2π0 and KS0K±π∓π+π− between threshold and 4.5 GeV
Experiment: BABAR (PEP-II)
Inspire ID: 2120528
Status: VALIDATED NOHEPDATA
Authors: - Peter Richardson
References: - arXiv: 2207.10340
Beams: e+ e-
Beam energies: ANY
Run details: - e+e- to hadrons, KS0 and pi0 should be set stable
Cross sections for e+e− → K+K−3π0, KS0K±π∓2π0 and KS0K±π∓π+π− between threshold and 4.5 GeV using radiative events. The cross sections for a number of resonant contributions are also measured.
Source
code:BABAR_2022_I2120528.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief e+e- -> KK 3pi
class BABAR_2022_I2120528 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2022_I2120528);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(FinalState(), "FS");
declare(UnstableParticles(), "UFS");
for (unsigned int ix = 0; ix < 10; ++ix) {
book(_sigma[ix], "TMP/n" + toString(ix + 1), refData(1 + ix, 1, 1));
}
}
void findChildren(const Particle& p, map<long, int>& nRes, int& ncount) {
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");
map<long, int> nCount;
int ntotal(0);
for (const Particle& p : fs.particles()) {
nCount[p.pid()] += 1;
++ntotal;
}
// stable particles
if (ntotal == 5) {
// K+K- 3pi0
if (nCount[-321] == 1 && nCount[321] == 1 && nCount[111] == 3) _sigma[0]->fill(sqrtS());
// KS0 Kpi 2pi0
else if (nCount[111] == 2 && nCount[310] == 1
&& ((nCount[321] == 1 && nCount[-211] == 1) || (nCount[-321] == 1 && nCount[211] == 1)))
_sigma[1]->fill(sqrtS());
// KS0 Kpi pi+pi-
else if (nCount[310] == 1
&& ((nCount[321] == 1 && nCount[-211] == 2 && nCount[211] == 1)
|| (nCount[-321] == 1 && nCount[211] == 2 && nCount[-211] == 1)))
_sigma[2]->fill(sqrtS());
}
// now the resonant states
// first K+K- eta and phi eta
const FinalState& ufs = apply<FinalState>(event, "UFS");
for (const Particle& p : ufs.particles(Cuts::pid == PID::ETA)) {
if (p.children().empty()) continue;
map<long, int> nRes = nCount;
int ncount = ntotal;
findChildren(p, nRes, ncount);
bool matched1 = false;
if (ncount == 2) {
matched1 = true;
for (const auto& val : nRes) {
if (abs(val.first) == PID::KPLUS) {
if (val.second != 1) {
matched1 = false;
break;
}
}
else if (val.second != 0) {
matched1 = false;
break;
}
}
if (matched1) {
_sigma[3]->fill(sqrtS());
}
}
bool matched2 = false;
for (const Particle& p2 : ufs.particles(Cuts::pid == PID::PHI)) {
if (p2.children().empty()) continue;
map<long, int> nRes2 = nRes;
int ncount2 = ncount;
findChildren(p2, nRes2, ncount2);
if (ncount2 != 0) continue;
matched2 = true;
for (const auto& val : nRes2) {
if (val.second != 0) {
matched2 = false;
break;
}
}
if (matched2) {
_sigma[4]->fill(sqrtS());
break;
}
}
if (matched1 || matched2) break;
}
// states with a K*
Particles Kstar = ufs.particles(Cuts::abspid == 313 or Cuts::abspid == 323);
for (unsigned int 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 matched1 = false;
if (ncount == 3) {
int idother = 310;
if (Kstar[ix].abspid() == 323) idother = -321 * (Kstar[ix].pid() / Kstar[ix].abspid());
for (const auto& val : nRes) {
if (val.first == idother) {
if (val.second != 1) {
matched1 = false;
break;
}
}
else if (val.first == PID::PI0) {
if (val.second != 2) {
matched1 = false;
break;
}
}
else if (val.second != 0) {
matched1 = false;
break;
}
}
if (matched1) {
if (Kstar[ix].abspid() == 321)
_sigma[7]->fill(sqrtS());
else
_sigma[6]->fill(sqrtS());
}
// K*+ K*-
bool matched2 = false;
for (unsigned int iy = 0; iy < ix + 1; ++iy) {
if (Kstar[iy].children().empty() || Kstar[iy].abspid() == 313
|| Kstar[iy].pid() != -Kstar[ix].pid()) {
continue;
}
map<long, int> nRes2 = nRes;
int ncount2 = ncount;
findChildren(Kstar[iy], nRes2, ncount2);
if (ncount2 != 1) continue;
matched2 = true;
for (const auto& val : nRes2) {
if (val.first == PID::PI0) {
if (val.second != 1) {
matched2 = false;
break;
}
}
if (val.second != 0) {
matched2 = false;
break;
}
}
if (matched2) {
_sigma[5]->fill(sqrtS());
break;
}
}
}
}
// finally f_1
for (const Particle& p : ufs.particles(Cuts::abspid == PID::RHOPLUS)) {
if (p.children().empty()) continue;
map<long, int> nRes = nCount;
int ncount = ntotal;
findChildren(p, nRes, ncount);
bool matched1 = false;
if (ncount == 3) {
int idother = -(p.pid() / p.abspid()) * 321;
matched1 = true;
for (const auto& val : nRes) {
if (val.first == PID::PI0 || val.first == idother || val.first == PID::K0S) {
if (val.second != 1) {
matched1 = false;
break;
}
}
else if (val.second != 0) {
matched1 = false;
break;
}
}
if (matched1) {
_sigma[8]->fill(sqrtS());
}
}
if (matched1) break;
}
// finally f_1
for (const Particle& p : ufs.particles(Cuts::pid == 20223)) {
if (p.children().empty()) continue;
map<long, int> nRes = nCount;
int ncount = ntotal;
findChildren(p, nRes, ncount);
bool matched1 = false;
if (ncount == 2) {
matched1 = true;
for (const auto& val : nRes) {
if (abs(val.first) == PID::PIPLUS) {
if (val.second != 1) {
matched1 = false;
break;
}
}
else if (val.second != 0) {
matched1 = false;
break;
}
}
if (matched1) {
_sigma[9]->fill(sqrtS());
}
}
if (matched1) break;
}
}
/// Normalise histograms etc., after the run
void finalize() {
const double fact = crossSection() / sumOfWeights() / nanobarn;
for (unsigned int ix = 0; ix < 10; ++ix) {
scale(_sigma[ix], fact);
Estimate1DPtr tmp;
book(tmp, 1 + ix, 1, 1);
barchart(_sigma[ix], tmp);
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _sigma[10];
/// @}
};
RIVET_DECLARE_PLUGIN(BABAR_2022_I2120528);
}