Rivet analyses
e+e− → DD̄π+π− for $\sqrt{s}=4.0854$ to 4.6 GeV
Experiment: BESIII (BEPC)
Inspire ID: 1725786
Status: VALIDATED NOHEPDATA SINGLEWEIGHT
Authors: - Peter Richardson
References: - Phys.Rev.D 100 (2019) 3, 032005
Beams: e+ e-
Beam energies: (2.0, 2.0); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.1, 2.1); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.2, 2.2); (2.3, 2.3); (2.3, 2.3); (2.3, 2.3)GeV
Run details: - e+ e- to hadrons
Analysis of the resonant contributions to e+e− → DD̄π+π− for $\sqrt{s}=4.0854$ to 4.6 GeV, where DD̄ = D+D−, D0D̄0. The cross sections for the production of π+π−ψ(3770) and D1(24200D̄0+c.c. are measured as a function of energy and the mass distrinutions are implemented for three energies.
Source
code:BESIII_2019_I1725786.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief e+ e- > D D pi pi
class BESIII_2019_I1725786 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2019_I1725786);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// projections
declare(FinalState(), "FS");
// histograms
for (double eVal : allowedEnergies()) {
const string en = toString(round(10*eVal/MeV));
if (isCompatibleWithSqrtS(eVal)) _sqs = en;
if (en == "44156"s) {
book(_h["Dpi0"], 1, 1, 1);
book(_h["Dpi1"], 1, 1, 2);
book(_h[en+"DD"], 2, 1, 3);
book(_h[en+"mass0"], 3, 2, 1);
book(_h[en+"mass1"], 3, 2, 2);
book(_h[en+"mass2"], 3, 2, 3);
}
else if (en == "42580"s) {
book(_h[en+"DD"], 2, 1, 1);
}
else if (en == "43583"s) {
book(_h[en+"DD"], 2, 1, 2);
book(_h[en+"mass0"], 3, 1, 1);
book(_h[en+"mass1"], 3, 1, 2);
book(_h[en+"mass2"], 3, 1, 3);
}
else if (en == "45995"s) {
book(_h[en+"mass0"], 3, 3, 1);
book(_h[en+"mass1"], 3, 3, 2);
book(_h[en+"mass2"], 3, 3, 3);
}
}
raiseBeamErrorIf(_sqs.empty());
size_t ih = 0;
for (size_t ix=0; ix<5; ++ix) {
if (ix==1) continue;
book(_sigma[ix], 4+ix,1,1);
if (ix!=0 && ix!=2) continue;
for (const string& en : _sigma[ix].binning().edges<0>()) {
const double eval = stod(en)*GeV;
if (isCompatibleWithSqrtS(eval)) {
_edge[ih] = en; break;
}
}
++ih;
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
Particles fs = apply<FinalState>(event, "FS").particles();
Particles DD,other;
for (const Particle& p : fs) {
Particle parent = p;
while (!parent.parents().empty()) {
parent=parent.parents()[0];
if (parent.abspid()==PID::D0 || parent.abspid()==PID::DPLUS) break;
}
if (parent.abspid()!=PID::D0 && parent.abspid()!=PID::DPLUS) {
other.push_back(p);
continue;
}
bool found=false;
for (const auto& D : DD) {
// D already in list
if (fuzzyEquals(D.mom(),parent.mom())) {
found=true;
break;
}
}
if (!found) DD += parent;
}
// d dbar + 2 other particles
if (DD.size()!=2 || other.size()!=2) vetoEvent;
// other particles pi+ pi-
if (!(other[0].pid()==-other[1].pid() && other[0].abspid()==PID::PIPLUS)) vetoEvent;
// d dbar pair
if (DD[0].pid() != -DD[1].pid()) vetoEvent;
if (other[0].pid()<0) swap(other[0],other[1]);
if (DD [0].pid()<0) swap(DD [0],DD [1]);
// fill the mass plots if needed
if (_sqs == "44156"s && DD[0].pid()==421) {
_h["Dpi0"]->fill((DD[0].mom()+other[0].mom()).mass());
_h["Dpi1"]->fill((DD[1].mom()+other[1].mom()).mass());
}
if (_sqs == "44156"s || _sqs == "42580"s || _sqs == "43583"s) {
_h[_sqs+"DD"]->fill((DD[0].mom()+DD[1].mom()).mass());
}
const bool DstarP = (DD[0].pid()== 421 && DD[0].parents()[0].pid()== 413);
const bool DstarM = (DD[1].pid()==-421 && DD[1].parents()[0].pid()==-413);
const bool Dstar = DstarP || DstarM;
if (_sqs == "44156"s || _sqs == "43583"s || _sqs == "45995"s) {
if (DD[0].pid()==421 && !Dstar) { // D0 pi+ pi- mass
_h[_sqs+"mass0"]->fill((DD[0].mom()+other[0].mom()+other[1].mom()).mass());
}
if (DstarP) { // D*+ pi- mass
_h[_sqs+"mass1"]->fill((DD[0].mom()+other[0].mom()+other[1].mom()).mass());
}
if (DD[0].pid()==411) { // D+ pi+ pi- mass
_h[_sqs+"mass2"]->fill((DD[0].mom()+other[0].mom()+other[1].mom()).mass());
}
}
// now for the counters for the cross sections
if (DD[0].parents()[0].pid()==30443 && DD[1].parents()[0].pid()==30443) {
_sigma[0]->fill(_edge[0]);
}
else if (DD[0].pid()==421 && (DD[0].parents()[0].pid()==10423 || DD[1].parents()[0].pid()==-10423)) {
_sigma[2]->fill(_edge[1]);
}
else if (DD[0].pid()==421 && ((DstarP && DD[0].parents()[0].parents()[0].pid()== 10423) ||
(DstarM && DD[1].parents()[0].parents()[0].pid()==-10423))) {
_sigma[3]->fill(_edge[1]);
}
else if (DD[0].pid()==411 && (DD[0].parents()[0].pid()==10413 || DD[1].parents()[0].pid()==-10413)) {
_sigma[4]->fill(_edge[1]);
}
}
/// Normalise histograms etc., after the run
void finalize() {
// dists
normalize(_h, 1.0, false);
// cross sections
const vector<double> brs = { 0.93, 1.0, 1.0, 0.677, 1.0};
const double fact = crossSection()/ sumOfWeights() /picobarn;;
for (size_t ih=0; ih<5; ++ih) {
if (ih==1) continue;
scale(_sigma[ih], fact/brs[ih]);
}
}
/// @}
/// @name Histograms
/// @{
map<string,Histo1DPtr> _h;
BinnedHistoPtr<string> _sigma[5];
string _edge[2], _sqs = "";
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2019_I1725786);
}