Rivet analyses
Topological distributions of inclusive three- and four-jet events
Experiment: D0 (Tevatron Run 1)
Inspire ID: 399364
Status: VALIDATED
Authors: - Frank Siegert
References: - Phys.Rev.D53:6000-6016,1996 - DOI: 10.1103/PhysRevD.53.6000 - arXiv: hep-ex/9509005
Beams: p- p+
Beam energies: (900.0, 900.0)GeV
Run details: - pp̄→ jets at 1800 GeV with minimum jet pT in analysis = 20 GeV
The global topologies of inclusive three- and four-jet events produced in pbar p interactions are described. The three- and four-jet events are selected from data recorded by the D0 detector at the Fermilab Tevatron Collider operating at a center-of-mass energy of $\sqrt{s}$=1800 GeV. The studies also show that the topological distributions of the different subprocesses involving different numbers of quarks are very similar and reproduce the measured distributions well. The parton-shower Monte Carlo generators provide a less satisfactory description of the topologies of the three- and four-jet events.
Source
code:D0_1996_I399364.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Math/LorentzTrans.hh"
namespace Rivet {
/// D0 topological distributions of 3- and 4-jet events.
class D0_1996_I399364 : public Analysis {
public:
RIVET_DEFAULT_ANALYSIS_CTOR(D0_1996_I399364);
/// @name Analysis methods
/// @{
/// Book histograms
void init() {
const FinalState fs;
/// @todo Use correct jet algorithm --- tried FJ3 D0RunICone but does
// not look as good as the Run2 cone alg used here
declare(FastJets(fs, JetAlg::D0ILCONE, 0.7), "ConeJets");
book(_h_3j_x3 ,1, 1, 1);
book(_h_3j_x5 ,2, 1, 1);
book(_h_3j_costheta3 ,3, 1, 1);
book(_h_3j_psi ,4, 1, 1);
book(_h_3j_mu34 ,5, 1, 1);
book(_h_3j_mu35 ,6, 1, 1);
book(_h_3j_mu45 ,7, 1, 1);
book(_h_4j_x3 ,8, 1, 1);
book(_h_4j_x4 ,9, 1, 1);
book(_h_4j_x5 ,10, 1, 1);
book(_h_4j_x6 ,11, 1, 1);
book(_h_4j_costheta3 ,12, 1, 1);
book(_h_4j_costheta4 ,13, 1, 1);
book(_h_4j_costheta5 ,14, 1, 1);
book(_h_4j_costheta6 ,15, 1, 1);
book(_h_4j_cosomega34 ,16, 1, 1);
book(_h_4j_cosomega35 ,17, 1, 1);
book(_h_4j_cosomega36 ,18, 1, 1);
book(_h_4j_cosomega45 ,19, 1, 1);
book(_h_4j_cosomega46 ,20, 1, 1);
book(_h_4j_cosomega56 ,21, 1, 1);
book(_h_4j_mu34 ,22, 1, 1);
book(_h_4j_mu35 ,23, 1, 1);
book(_h_4j_mu36 ,24, 1, 1);
book(_h_4j_mu45 ,25, 1, 1);
book(_h_4j_mu46 ,26, 1, 1);
book(_h_4j_mu56 ,27, 1, 1);
book(_h_4j_theta_BZ ,28, 1, 1);
book(_h_4j_costheta_NR ,29, 1, 1);
}
void analyze(const Event& event) {
Jets jets_in = apply<FastJets>(event, "ConeJets")
.jets(Cuts::Et > 20*GeV && Cuts::abseta < 3, cmpMomByEt);
Jets jets_isolated;
for (size_t i = 0; i < jets_in.size(); ++i) {
bool isolated = true;
for (size_t j = 0; j < jets_in.size(); ++j) {
if (i != j && deltaR(jets_in[i], jets_in[j]) < 1.4) {
isolated = false;
break;
}
}
if (isolated) jets_isolated.push_back(jets_in[i]);
}
if (jets_isolated.empty() || jets_isolated[0].Et() < 60.0*GeV) vetoEvent;
if (jets_isolated.size() > 2) _threeJetAnalysis(jets_isolated);
if (jets_isolated.size() > 3) _fourJetAnalysis(jets_isolated);
}
void finalize() {
normalize(_h_3j_x3);
normalize(_h_3j_x5);
normalize(_h_3j_costheta3);
normalize(_h_3j_psi);
normalize(_h_3j_mu34);
normalize(_h_3j_mu35);
normalize(_h_3j_mu45);
normalize(_h_4j_x3);
normalize(_h_4j_x4);
normalize(_h_4j_x5);
normalize(_h_4j_x6);
normalize(_h_4j_costheta3);
normalize(_h_4j_costheta4);
normalize(_h_4j_costheta5);
normalize(_h_4j_costheta6);
normalize(_h_4j_cosomega34);
normalize(_h_4j_cosomega35);
normalize(_h_4j_cosomega36);
normalize(_h_4j_cosomega45);
normalize(_h_4j_cosomega46);
normalize(_h_4j_cosomega56);
normalize(_h_4j_mu34);
normalize(_h_4j_mu35);
normalize(_h_4j_mu36);
normalize(_h_4j_mu45);
normalize(_h_4j_mu46);
normalize(_h_4j_mu56);
normalize(_h_4j_theta_BZ);
normalize(_h_4j_costheta_NR);
}
/// @}
private:
/// @name Helper functions
/// @{
void _threeJetAnalysis(const Jets& jets) {
// >=3 jet events
FourMomentum jjj(jets[0].mom() + jets[1].mom() + jets[2].mom());
const double sqrts = _safeMass(jjj);
if (sqrts<200*GeV) return;
const LorentzTransform cms_boost = LorentzTransform::mkFrameTransformFromBeta(jjj.betaVec());
vector<FourMomentum> jets_boosted;
for (Jet jet : jets) {
jets_boosted.push_back(cms_boost.transform(jet.mom()));
}
isortBy(jets_boosted, cmpMomByE);
FourMomentum p3(jets_boosted[0]);
FourMomentum p4(jets_boosted[1]);
FourMomentum p5(jets_boosted[2]);
Vector3 beam1(0.0, 0.0, 1.0);
Vector3 p1xp3 = beam1.cross(p3.p3());
Vector3 p4xp5 = p4.p3().cross(p5.p3());
const double cospsi = p1xp3.dot(p4xp5)/p1xp3.mod()/p4xp5.mod();
_h_3j_x3->fill(2.0*p3.E()/sqrts);
_h_3j_x5->fill(2.0*p5.E()/sqrts);
_h_3j_costheta3->fill(fabs(cos(p3.theta())));
_h_3j_psi->fill(acos(cospsi)/degree);
_h_3j_mu34->fill(_safeMass(FourMomentum(p3+p4))/sqrts);
_h_3j_mu35->fill(_safeMass(FourMomentum(p3+p5))/sqrts);
_h_3j_mu45->fill(_safeMass(FourMomentum(p4+p5))/sqrts);
}
void _fourJetAnalysis(const Jets& jets) {
// >=4 jet events
FourMomentum jjjj(jets[0].momentum() + jets[1].momentum() + jets[2].momentum()+ jets[3].momentum());
const double sqrts = _safeMass(jjjj);
if (sqrts < 200*GeV) return;
const LorentzTransform cms_boost = LorentzTransform::mkFrameTransformFromBeta(jjjj.betaVec());
vector<FourMomentum> jets_boosted;
for (Jet jet : jets) {
jets_boosted.push_back(cms_boost.transform(jet.momentum()));
}
isortBy(jets_boosted, cmpMomByE);
FourMomentum p3(jets_boosted[0]);
FourMomentum p4(jets_boosted[1]);
FourMomentum p5(jets_boosted[2]);
FourMomentum p6(jets_boosted[3]);
Vector3 p3xp4 = p3.p3().cross(p4.p3());
Vector3 p5xp6 = p5.p3().cross(p6.p3());
const double costheta_BZ = p3xp4.dot(p5xp6)/p3xp4.mod()/p5xp6.mod();
const double costheta_NR = (p3.p3()-p4.p3()).dot(p5.p3()-p6.p3())/
(p3.p3()-p4.p3()).mod()/(p5.p3()-p6.p3()).mod();
_h_4j_x3->fill(2.0*p3.E()/sqrts);
_h_4j_x4->fill(2.0*p4.E()/sqrts);
_h_4j_x5->fill(2.0*p5.E()/sqrts);
_h_4j_x6->fill(2.0*p6.E()/sqrts);
_h_4j_costheta3->fill(fabs(cos(p3.theta())));
_h_4j_costheta4->fill(fabs(cos(p4.theta())));
_h_4j_costheta5->fill(fabs(cos(p5.theta())));
_h_4j_costheta6->fill(fabs(cos(p6.theta())));
_h_4j_cosomega34->fill(cos(p3.angle(p4)));
_h_4j_cosomega35->fill(cos(p3.angle(p5)));
_h_4j_cosomega36->fill(cos(p3.angle(p6)));
_h_4j_cosomega45->fill(cos(p4.angle(p5)));
_h_4j_cosomega46->fill(cos(p4.angle(p6)));
_h_4j_cosomega56->fill(cos(p5.angle(p6)));
_h_4j_mu34->fill(_safeMass(FourMomentum(p3+p4))/sqrts);
_h_4j_mu35->fill(_safeMass(FourMomentum(p3+p5))/sqrts);
_h_4j_mu36->fill(_safeMass(FourMomentum(p3+p6))/sqrts);
_h_4j_mu45->fill(_safeMass(FourMomentum(p4+p5))/sqrts);
_h_4j_mu46->fill(_safeMass(FourMomentum(p4+p6))/sqrts);
_h_4j_mu56->fill(_safeMass(FourMomentum(p5+p6))/sqrts);
_h_4j_theta_BZ->fill(acos(fabs(costheta_BZ))/degree);
_h_4j_costheta_NR->fill(fabs(costheta_NR));
}
double _safeMass(const FourMomentum& p) {
double mass2=p.mass2();
if (mass2>0.0) return sqrt(mass2);
else if (mass2<-1.0e-5) {
MSG_WARNING("m2 = " << mass2/GeV << " GeV. Assuming m2 = 0.");
return 0.0;
}
else return 0.0;
}
/// @}
private:
/// @name Histograms
/// @{
Histo1DPtr _h_3j_x3;
Histo1DPtr _h_3j_x5;
Histo1DPtr _h_3j_costheta3;
Histo1DPtr _h_3j_psi;
Histo1DPtr _h_3j_mu34;
Histo1DPtr _h_3j_mu35;
Histo1DPtr _h_3j_mu45;
Histo1DPtr _h_4j_x3;
Histo1DPtr _h_4j_x4;
Histo1DPtr _h_4j_x5;
Histo1DPtr _h_4j_x6;
Histo1DPtr _h_4j_costheta3;
Histo1DPtr _h_4j_costheta4;
Histo1DPtr _h_4j_costheta5;
Histo1DPtr _h_4j_costheta6;
Histo1DPtr _h_4j_cosomega34;
Histo1DPtr _h_4j_cosomega35;
Histo1DPtr _h_4j_cosomega36;
Histo1DPtr _h_4j_cosomega45;
Histo1DPtr _h_4j_cosomega46;
Histo1DPtr _h_4j_cosomega56;
Histo1DPtr _h_4j_mu34;
Histo1DPtr _h_4j_mu35;
Histo1DPtr _h_4j_mu36;
Histo1DPtr _h_4j_mu45;
Histo1DPtr _h_4j_mu46;
Histo1DPtr _h_4j_mu56;
Histo1DPtr _h_4j_theta_BZ;
Histo1DPtr _h_4j_costheta_NR;
/// @}
};
RIVET_DECLARE_ALIASED_PLUGIN(D0_1996_I399364, D0_1996_S3214044);
}Aliases: - D0_1996_S3214044