Rivet analyses
Spectra for π±, K±, KS0 and p̄ in e+e− collisions at the Υ(1S) and continuum
Experiment: ARGUS (DORIS)
Inspire ID: 276860
Status: VALIDATED
Authors: - Peter Richardson
References: - Z.Phys. C44 (1989) 547, 1989
Beams: e- e+
Beam energies: (4.7, 4.7); (5.0, 5.0)GeV
Run details: - e+e− analysis near the Υ resonances
Spectra for the production of π±, K±, KS0 and p̄ in e+e− collisions. Data are taken on the Υ(1S) and in the nearby continuum.
Source
code:ARGUS_1989_I276860.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief pi+- K+- K0S pbar spectra continuum and Upsilon 1s
class ARGUS_1989_I276860 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1989_I276860);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(FinalState(), "FS");
declare(UnstableParticles(), "UFS");
// Book histograms
book(_h_pi_ups1_p, 5, 1, 1);
book(_h_pi_cont_p, 5, 1, 2);
book(_h_pi_ups1_z, 9, 1, 1);
book(_h_pi_cont_z, 9, 1, 2);
book(_h_Kp_ups1_p, 6, 1, 1);
book(_h_Kp_cont_p, 6, 1, 2);
book(_h_Kp_ups1_z, 10, 1, 1);
book(_h_Kp_cont_z, 10, 1, 2);
book(_h_KS_ups1_p, 7, 1, 1);
book(_h_KS_cont_p, 7, 1, 2);
book(_h_KS_ups1_z, 11, 1, 1);
book(_h_KS_cont_z, 11, 1, 2);
book(_h_pt_ups1_p, 8, 1, 1);
book(_h_pt_cont_p, 8, 1, 2);
book(_h_pt_ups1_z, 12, 1, 1);
book(_h_pt_cont_z, 12, 1, 2);
// Counters
book(_n_PiA, 1, 1, 1);
book(_n_PiB, 1, 1, 2);
book(_n_KS, 2, 1, 1);
book(_n_Kp, 3, 1, 1);
book(_n_ptA, 4, 1, 1);
book(_n_ptB, 4, 1, 2);
// weights
book(_weightSum_cont, "/TMP/weightSum_cont");
book(_weightSum_Ups1, "/TMP/weightSum_Ups1");
}
/// Recursively walk the decay tree to find decay products of @a p
void findDecayProducts(Particle mother, Particles& unstable) {
for (const Particle& p : mother.children()) {
const int id = abs(p.pid());
if (id == 211 || id == 2212 || id == 310 || id == 130 || id == 321) {
unstable.push_back(p);
}
if (!p.children().empty()) findDecayProducts(p, unstable);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Find the Upsilons among the unstables
const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
const FinalState& fs = apply<FinalState>(event, "FS");
Particles upsilons = ufs.particles(Cuts::pid == 553);
// Continuum
if (upsilons.empty()) {
MSG_DEBUG("No Upsilons found => continuum event");
_weightSum_cont->fill();
// stable particles
for (const Particle& p :
fs.particles(Cuts::abspid == 211 or Cuts::abspid == 2212 or Cuts::abspid == 321)) {
const int id = abs(p.pid());
const double xE = 2. * p.E() / sqrtS();
const double modp = p.p3().mod();
const double beta = modp / p.E();
int idMom = !p.parents().empty() ? abs(p.parents()[0].pid()) : 0;
if (id == 211) {
// not from K0S or Lambda decays
if (idMom != 310 && idMom != 3122) {
_h_pi_cont_p->fill(modp);
_h_pi_cont_z->fill(xE, 1. / beta);
_n_PiA->fill("9.98"s);
}
_n_PiB->fill("9.98"s);
}
else if (id == 321) {
_h_Kp_cont_p->fill(modp);
_h_Kp_cont_z->fill(xE, 1. / beta);
_n_Kp->fill("9.98"s);
}
else if (id == 2212) {
// not from K0S or Lambda decays
if (idMom != 310 && idMom != 3122) {
_h_pt_cont_p->fill(modp);
_h_pt_cont_z->fill(xE, 1. / beta);
_n_ptA->fill("9.98"s);
}
_n_ptB->fill("9.98"s);
}
}
// Unstable particles
for (const Particle& p : ufs.particles(Cuts::pid == 310 || Cuts::pid == 130)) {
const double xE = 2. * p.E() / sqrtS();
const double modp = p.p3().mod();
const double beta = modp / p.E();
_h_KS_cont_p->fill(modp);
_h_KS_cont_z->fill(xE, 1. / beta);
_n_KS->fill("9.98"s);
}
}
// Upsilon(s) found
else {
MSG_DEBUG("Upsilons found => resonance event");
for (const Particle& ups : upsilons) {
_weightSum_Ups1->fill();
Particles unstable;
// Find the decay products we want
findDecayProducts(ups, unstable);
LorentzTransform cms_boost;
if (ups.p3().mod() > 1 * MeV)
cms_boost = LorentzTransform::mkFrameTransformFromBeta(ups.momentum().betaVec());
const double mass = ups.mass();
// loop over decay products
for (const Particle& p : unstable) {
const int id = abs(p.pid());
const FourMomentum p2 = cms_boost.transform(p.momentum());
const double xE = 2. * p2.E() / mass;
const double modp = p2.p3().mod();
const double beta = modp / p2.E();
int idMom = !p.parents().empty() ? abs(p.parents()[0].pid()) : 0;
if (id == 211) {
// not from K0S or Lambda decays
if (idMom != 310 && idMom != 3122) {
_h_pi_ups1_p->fill(modp);
_h_pi_ups1_z->fill(xE, 1. / beta);
_n_PiA->fill("9.46"s);
}
_n_PiB->fill("9.46"s);
}
else if (id == 321) {
_h_Kp_ups1_p->fill(modp);
_h_Kp_ups1_z->fill(xE, 1. / beta);
_n_Kp->fill("9.46"s);
}
else if (id == 2212) {
// not from K0S or Lambda decays
if (idMom != 310 && idMom != 3122) {
_h_pt_ups1_p->fill(modp);
_h_pt_ups1_z->fill(xE, 1. / beta);
_n_ptA->fill("9.46"s);
}
_n_ptB->fill("9.46"s);
}
else if (id == 310 || id == 130) {
_h_KS_ups1_p->fill(modp);
_h_KS_ups1_z->fill(xE, 1. / beta);
_n_KS->fill("9.46"s);
}
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
// Scale histos
if (_weightSum_cont->val() > 0.) {
scale(_h_pi_cont_p, 1. / *_weightSum_cont);
scale(_h_Kp_cont_p, 1. / *_weightSum_cont);
scale(_h_KS_cont_p, 1. / *_weightSum_cont);
scale(_h_pt_cont_p, 1. / *_weightSum_cont);
scale(_h_pi_cont_z, 1. / *_weightSum_cont);
scale(_h_Kp_cont_z, 1. / *_weightSum_cont);
scale(_h_KS_cont_z, 1. / *_weightSum_cont);
scale(_h_pt_cont_z, 1. / *_weightSum_cont);
}
if (_weightSum_Ups1->val() > 0.) {
scale(_h_pi_ups1_p, 1. / *_weightSum_Ups1);
scale(_h_Kp_ups1_p, 1. / *_weightSum_Ups1);
scale(_h_KS_ups1_p, 1. / *_weightSum_Ups1);
scale(_h_pt_ups1_p, 1. / *_weightSum_Ups1);
scale(_h_pi_ups1_z, 1. / *_weightSum_Ups1);
scale(_h_Kp_ups1_z, 1. / *_weightSum_Ups1);
scale(_h_KS_ups1_z, 1. / *_weightSum_Ups1);
scale(_h_pt_ups1_z, 1. / *_weightSum_Ups1);
}
// Counters
vector<CounterPtr> scales = {_weightSum_Ups1, _weightSum_cont};
vector<string> labels = {"9.46", "9.98"};
for (unsigned int ix = 0; ix < 2; ++ix) {
_n_PiA->binAt(labels[ix]).scaleW(1. / scales[ix]->val());
_n_PiB->binAt(labels[ix]).scaleW(1. / scales[ix]->val());
_n_Kp->binAt(labels[ix]).scaleW(1. / scales[ix]->val());
_n_KS->binAt(labels[ix]).scaleW(1. / scales[ix]->val());
_n_ptA->binAt(labels[ix]).scaleW(1. / scales[ix]->val());
_n_ptB->binAt(labels[ix]).scaleW(1. / scales[ix]->val());
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_pi_ups1_p, _h_pi_cont_p, _h_pi_ups1_z, _h_pi_cont_z;
Histo1DPtr _h_Kp_ups1_p, _h_Kp_cont_p, _h_Kp_ups1_z, _h_Kp_cont_z;
Histo1DPtr _h_KS_ups1_p, _h_KS_cont_p, _h_KS_ups1_z, _h_KS_cont_z;
Histo1DPtr _h_pt_ups1_p, _h_pt_cont_p, _h_pt_ups1_z, _h_pt_cont_z;
// Counters
BinnedHistoPtr<string> _n_PiA, _n_PiB, _n_Kp, _n_KS, _n_ptA, _n_ptB;
CounterPtr _weightSum_cont, _weightSum_Ups1;
/// @}
};
RIVET_DECLARE_PLUGIN(ARGUS_1989_I276860);
}