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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/DISKinematics.hh"
#include "Rivet/Projections/DISFinalState.hh"
#include "Rivet/Projections/FastJets.hh"
namespace Rivet {
namespace H1_2007_I746380_PROJECTIONS {
/// Projection to find the largest gaps and the masses of the two
/// systems separated by the gap. Based on the HZTools gap-finding
/// method (hzhadgap.F). Note that gaps are found in the HCM frame.
///
/// @author Christine O. Rasmussen.
class RapidityGap : public Projection {
public:
/// Type of DIS boost to apply
enum Frame { HCM, LAB, XCM };
RapidityGap() {
setName("RapidityGap");
declare(DISKinematics(), "DISKIN");
declare(DISFinalState(DISFinalState::BoostFrame::HCM), "DISFS");
}
DEFAULT_RIVET_PROJ_CLONE(RapidityGap);
double M2X() const { return _M2X; }
double M2Y() const { return _M2Y; }
double t() const { return _t; }
double gap() const { return _gap; }
double gapUpp() const { return _gapUpp; }
double gapLow() const { return _gapLow; }
double EpPzX(Frame f) const {
if (f == LAB) return _ePpzX_LAB;
else if (f == XCM) return _ePpzX_XCM;
else return _ePpzX_HCM;
}
double EmPzX(Frame f) const {
if (f == LAB) return _eMpzX_LAB;
else if (f == XCM) return _eMpzX_XCM;
else return _eMpzX_HCM;
}
FourMomentum pX(Frame f) const {
if (f == LAB) return _momX_LAB;
else if (f == XCM) return _momX_XCM;
else return _momX_HCM;
}
FourMomentum pY(Frame f) const {
if (f == LAB) return _momY_LAB;
else if (f == XCM) return _momY_XCM;
else return _momY_HCM;
}
const Particles& systemX(Frame f) const {
if (f == LAB) return _pX_LAB;
else if (f == XCM) return _pX_XCM;
else return _pX_HCM;
}
const Particles& systemY(Frame f) const {
if (f == LAB) return _pY_LAB;
else if (f == XCM) return _pY_XCM;
else return _pY_HCM;
}
protected:
virtual CmpState compare(const Projection& p) const {
const RapidityGap& other = pcast<RapidityGap>(p);
return mkNamedPCmp(other, "DISKIN") || mkNamedPCmp(other, "DISFS");
}
virtual void project(const Event& e){
const DISKinematics& dk = apply<DISKinematics>(e, "DISKIN");
const Particles& p = apply<DISFinalState>(e, "DISFS").particles(cmpMomByEta);
findgap(p, dk);
}
void clearAll(){
_M2X = _M2Y = _t = _gap = 0.;
_gapUpp = _gapLow = -8.;
_ePpzX_HCM = _eMpzX_HCM =_ePpzX_LAB = _eMpzX_LAB = _ePpzX_XCM = _eMpzX_XCM = 0.;
_momX_HCM.setPE(0., 0., 0., 0.);
_momY_HCM.setPE(0., 0., 0., 0.);
_momX_XCM.setPE(0., 0., 0., 0.);
_momY_XCM.setPE(0., 0., 0., 0.);
_momX_LAB.setPE(0., 0., 0., 0.);
_momY_LAB.setPE(0., 0., 0., 0.);
_pX_HCM.clear();
_pY_HCM.clear();
_pX_XCM.clear();
_pY_XCM.clear();
_pX_LAB.clear();
_pY_LAB.clear();
}
void findgap(const Particles& particles, const DISKinematics& diskin){
clearAll();
// Begin by finding largest gap and gapedges between all final
// state particles in HCM frame.
int nP = particles.size();
int dir = diskin.orientation();
for (int i = 0; i < nP-1; ++i){
double tmpGap = abs(particles[i+1].eta() - particles[i].eta());
if (tmpGap > _gap) {
_gap = tmpGap;
_gapLow = (dir > 0) ? particles[i].eta() : dir * particles[i+1].eta();
_gapUpp = (dir > 0) ? particles[i+1].eta() : dir * particles[i].eta();
}
}
// Define the two systems X and Y.
Particles tmp_pX, tmp_pY;
for (const Particle& ip : particles) {
if (dir * ip.eta() > _gapLow) tmp_pX.push_back(ip);
else tmp_pY.push_back(ip);
}
Particles pX, pY;
pX = (dir < 0) ? tmp_pY : tmp_pX;
pY = (dir < 0) ? tmp_pX : tmp_pY;
// Find variables related to HCM frame.
// Note that HCM has photon along +z, as opposed to
// H1 where proton is along +z. This results in a sign change
// as compared to H1 papers!
// X - side
FourMomentum momX;
for (const Particle& jp : pX) {
momX += jp.momentum();
_ePpzX_HCM += jp.E() - jp.pz(); // Sign + => -
_eMpzX_HCM += jp.E() + jp.pz(); // Sign - => +
}
_momX_HCM = momX;
_pX_HCM = pX;
_M2X = _momX_HCM.mass2();
// Y - side
FourMomentum momY;
for (const Particle& kp : pY) momY += kp.momentum();
_momY_HCM = momY;
_pY_HCM = pY;
_M2Y = _momY_HCM.mass2();
// Find variables related to LAB frame
const LorentzTransform hcmboost = diskin.boostHCM();
const LorentzTransform hcminverse = hcmboost.inverse();
_momX_LAB = hcminverse.transform(_momX_HCM);
_momY_LAB = hcminverse.transform(_momY_HCM);
// Find momenta in XCM frame. Note that it is HCM frame that is
// boosted, resulting in a sign change later!
const bool doXCM = (momX.betaVec().mod2() < 1.);
if (doXCM) {
const LorentzTransform xcmboost =
LorentzTransform::mkFrameTransformFromBeta(momX.betaVec());
_momX_XCM = xcmboost.transform(momX);
_momY_XCM = xcmboost.transform(momY);
}
for (const Particle& jp : pX) {
// Boost from HCM to LAB.
FourMomentum lab = hcminverse.transform(jp.momentum());
_ePpzX_LAB += lab.E() + dir * lab.pz();
_eMpzX_LAB += lab.E() - dir * lab.pz();
Particle plab = jp;
plab.setMomentum(lab);
_pX_LAB.push_back(plab);
// Set XCM. Note that since HCM frame is boosted to XCM frame,
// we have a sign change
if (doXCM) {
const LorentzTransform xcmboost =
LorentzTransform::mkFrameTransformFromBeta(_momX_HCM.betaVec());
FourMomentum xcm = xcmboost.transform(jp.momentum());
_ePpzX_XCM += xcm.E() - xcm.pz(); // Sign + => -
_eMpzX_XCM += xcm.E() + xcm.pz(); // Sign - => +
Particle pxcm = jp;
pxcm.setMomentum(xcm);
_pX_XCM.push_back(pxcm);
}
}
for (const Particle& jp : pY) {
// Boost from HCM to LAB
FourMomentum lab = hcminverse.transform(jp.momentum());
Particle plab = jp;
plab.setMomentum(lab);
_pY_LAB.push_back(plab);
// Boost from HCM to XCM
if (doXCM) {
const LorentzTransform xcmboost =
LorentzTransform::mkFrameTransformFromBeta(_momX_HCM.betaVec());
FourMomentum xcm = xcmboost.transform(jp.momentum());
Particle pxcm = jp;
pxcm.setMomentum(xcm);
_pY_XCM.push_back(pxcm);
}
}
// Find t: Currently can only handle gap on proton side.
// @TODO: Expand to also handle gap on photon side
// Boost p from LAB to HCM frame to find t.
const FourMomentum proton = hcmboost.transform(diskin.beamHadron().momentum());
FourMomentum pPom = proton - _momY_HCM;
_t = pPom * pPom;
}
private:
double _M2X, _M2Y, _t;
double _gap, _gapUpp, _gapLow;
double _ePpzX_LAB, _eMpzX_LAB, _ePpzX_HCM, _eMpzX_HCM, _ePpzX_XCM, _eMpzX_XCM;
FourMomentum _momX_HCM, _momY_HCM,_momX_LAB, _momY_LAB, _momX_XCM, _momY_XCM;
Particles _pX_HCM, _pY_HCM, _pX_LAB, _pY_LAB, _pX_XCM, _pY_XCM;
};
/// Projection to boost system X (photon+Pomeron) particles into its rest frame.
///
/// @author Ilkka Helenius
class BoostedXSystem : public FinalState {
public:
BoostedXSystem(const FinalState& fs) {
setName("BoostedXSystem");
declare(fs,"FS");
declare(RapidityGap(), "RAPGAP");
}
// Return the boost to XCM frame.
const LorentzTransform& boost() const { return _boost; }
DEFAULT_RIVET_PROJ_CLONE(BoostedXSystem);
protected:
// Apply the projection on the supplied event.
void project(const Event& e){
const RapidityGap& rg = apply<RapidityGap>(e, "RAPGAP");
// Total momentum of the system X.
const FourMomentum pX = rg.pX(RapidityGap::HCM);
// Reset the boost. Is there a separate method for this?
_boost = combine(_boost, _boost.inverse());
// Define boost only when numerically safe, otherwise negligible.
if (pX.betaVec().mod2() < 1.)
_boost = LorentzTransform::mkFrameTransformFromBeta(pX.betaVec());
// Boost the particles from system X.
_theParticles.clear();
_theParticles.reserve(rg.systemX(RapidityGap::HCM).size());
for (const Particle& p : rg.systemX(RapidityGap::HCM)) {
Particle temp = p;
temp.setMomentum(_boost.transform(temp.momentum()));
_theParticles.push_back(temp);
}
}
// Compare projections.
CmpState compare(const Projection& p) const {
const BoostedXSystem& other = pcast<BoostedXSystem>(p);
return mkNamedPCmp(other, "RAPGAP") || mkNamedPCmp(other, "FS");
}
private:
LorentzTransform _boost;
};
}
/// @brief H1 diffractive dijets
///
/// Diffractive dijets H1 with 920 GeV p and 27.5 GeV e
/// Note tagged protons!
///
/// @author Christine O. Rasmussen
class H1_2007_I746380 : public Analysis {
public:
typedef H1_2007_I746380_PROJECTIONS::RapidityGap RapidityGap;
typedef H1_2007_I746380_PROJECTIONS::BoostedXSystem BoostedXSystem;
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(H1_2007_I746380);
/// @name Analysis methods
//@{
// Book projections and histograms
void init() {
declare(DISKinematics(), "Kinematics");
const DISFinalState& disfs = declare(DISFinalState(DISFinalState::BoostFrame::HCM), "DISFS");
const BoostedXSystem& disfsXcm = declare( BoostedXSystem(disfs), "BoostedXFS");
declare(FastJets(disfsXcm, fastjet::JetAlgorithm::kt_algorithm, fastjet::RecombinationScheme::pt_scheme, 1.0,
JetAlg::Muons::ALL, JetAlg::Invisibles::NONE, nullptr), "DISFSJets");
declare(RapidityGap(), "RapidityGap");
// Book histograms from REF data
book(_h_DIS_dsigdzPom, 1, 1, 1);
book(_h_DIS_dsigdlogXpom, 2, 1, 1);
book(_h_DIS_dsigdW, 3, 1, 1);
book(_h_DIS_dsigdQ2, 4, 1, 1);
book(_h_DIS_dsigdEtJet1, 5, 1, 1);
book(_h_DIS_dsigdAvgEta, 6, 1, 1);
book(_h_DIS_dsigdDeltaEta, 7, 1, 1);
book(_h_PHO_dsigdzPom, 8, 1, 1);
book(_h_PHO_dsigdxGam, 9, 1, 1);
book(_h_PHO_dsigdlogXpom, 10, 1, 1);
book(_h_PHO_dsigdW, 11, 1, 1);
book(_h_PHO_dsigdEtJet1, 12, 1, 1);
book(_h_PHO_dsigdAvgEta, 13, 1, 1);
book(_h_PHO_dsigdDeltaEta, 14, 1, 1);
book(_h_PHO_dsigdMjets, 15, 1, 1);
isDIS = false;
nVeto0 = 0;
nVeto1 = 0;
nVeto2 = 0;
nVeto3 = 0;
nVeto4 = 0;
nVeto5 = 0;
nPHO = 0;
nDIS = 0;
}
// Do the analysis
void analyze(const Event& event) {
// Event weight
isDIS = false;
// Projections - special handling of events where no proton found:
const RapidityGap& rg = apply<RapidityGap>(event, "RapidityGap");
const DISKinematics& kin = apply<DISKinematics>(event, "Kinematics");
const BoostedXSystem& disfsXcm = apply<BoostedXSystem>( event, "BoostedXFS");
// Determine kinematics: H1 has +z = proton direction
int dir = kin.orientation();
double W2 = kin.W2();
double W = sqrt(W2);
double y = kin.y();
double Q2 = kin.Q2();
// Separate into DIS and PHO regimes else veto
if (!inRange(W, 165.*GeV, 242.*GeV)) vetoEvent;
if (Q2 < 0.01*GeV2) {
isDIS = false;
++nPHO;
} else if (inRange(Q2, 4.0*GeV2, 80.*GeV2)) {
isDIS = true;
++nDIS;
} else {
vetoEvent;
}
++nVeto0;
// Find diffractive variables as defined in paper.
const double M2Y = rg.M2Y();
const double M2X = rg.M2X();
const double abst = abs(rg.t());
const double xPom = (isDIS) ? (Q2 + M2X) / (Q2 + W2) :
rg.EpPzX(RapidityGap::LAB) / (2. * kin.beamHadron().E());
// Veto if outside allowed region
if (sqrt(M2Y) > 1.6*GeV) vetoEvent;
++nVeto1;
if (abst > 1.0*GeV2) vetoEvent;
++nVeto2;
if (xPom > 0.03) vetoEvent;
++nVeto3;
// Jet selection. Note jets are found in photon-proton (XCM)
// frame, but eta cut is applied in lab frame!
Cut jetcuts = Cuts::Et > 4.* GeV;
Jets jets = apply<FastJets>(event, "DISFSJets").jets(jetcuts, cmpMomByEt);
// Veto if not dijets and if Et_j1 < 5.0
if (jets.size() < 2) vetoEvent;
if (jets[0].Et() < 5.*GeV) vetoEvent;
++nVeto4;
// Find Et_jet1 and deltaEta* in XCM frame
double EtJet1 = jets[0].Et() * GeV;
double etaXCMJet1 = jets[0].eta();
double etaXCMJet2 = jets[1].eta();
double deltaEtaJets = abs(etaXCMJet1 - etaXCMJet2);
// Transform from XCM to HCM
const LorentzTransform xcmboost = disfsXcm.boost();
for (int i = 0; i < 2; ++i) jets[i].transformBy(xcmboost.inverse());
// Find mass of jets and EpPz, EmPz of jets
FourMomentum momJets = jets[0].momentum() + jets[1].momentum();
double M2jets = momJets.mass2();
double EpPzJets = 0.;
double EmPzJets = 0.;
// DIS variables are found in XCM frame, so boost back again
if (isDIS){
for (int i = 0; i < 2; ++i) jets[i].transformBy(xcmboost);
}
// Note sign change wrt. H1 because photon is in +z direction
// Jets in HCM so no need to consider orientation.
for (int i = 0; i < 2; ++i){
EpPzJets += jets[i].E() - jets[i].pz(); // Sign: + => -
EmPzJets += jets[i].E() + jets[i].pz(); // Sign: - => +
}
// Transform the jets from HCM to LAB frame where eta cut is
// applied for photoproduction.
const LorentzTransform hcmboost = kin.boostHCM();
for (int i = 0; i < 2; ++i) jets[i].transformBy(hcmboost.inverse());
double etaLabJet1 = dir * jets[0].eta();
double etaLabJet2 = dir * jets[1].eta();
double etaMin = (isDIS) ? -3. : -1.;
double etaMax = (isDIS) ? 0. : 2.;
double eta1 = (isDIS) ? etaXCMJet1 : etaLabJet1;
double eta2 = (isDIS) ? etaXCMJet2 : etaLabJet2;
if (!inRange(eta1, etaMin, etaMax)) vetoEvent;
if (!inRange(eta2, etaMin, etaMax)) vetoEvent;
++nVeto5;
// Pseudorapidity distributions are examined in lab frame:
double avgEtaJets = 0.5 * (etaLabJet1 + etaLabJet2);
// Derive xPom and xGam values from the jet kinematics.
double zPomJets, xGamJets;
if (isDIS) {
zPomJets = (Q2 + M2jets) / (Q2 + M2X);
xGamJets = EmPzJets / rg.EmPzX(RapidityGap::XCM);
} else {
// Boost E_p, E_e to HCM frame
FourMomentum lep = hcmboost.transform(kin.beamLepton().momentum());
FourMomentum had = hcmboost.transform(kin.beamHadron().momentum());
zPomJets = EpPzJets / (2. * xPom * had.E());
xGamJets = EmPzJets / (2. * y * lep.E());
}
// Now fill histograms
if (isDIS){
_h_DIS_dsigdzPom ->fill(zPomJets);
_h_DIS_dsigdlogXpom ->fill(log10(xPom));
_h_DIS_dsigdW ->fill(W);
_h_DIS_dsigdQ2 ->fill(Q2);
_h_DIS_dsigdEtJet1 ->fill(EtJet1);
_h_DIS_dsigdAvgEta ->fill(avgEtaJets);
_h_DIS_dsigdDeltaEta ->fill(deltaEtaJets);
} else {
_h_PHO_dsigdzPom ->fill(zPomJets);
_h_PHO_dsigdxGam ->fill(xGamJets);
_h_PHO_dsigdlogXpom ->fill(log10(xPom));
_h_PHO_dsigdW ->fill(W);
_h_PHO_dsigdEtJet1 ->fill(EtJet1);
_h_PHO_dsigdAvgEta ->fill(avgEtaJets);
_h_PHO_dsigdDeltaEta ->fill(deltaEtaJets);
_h_PHO_dsigdMjets ->fill(sqrt(M2jets));
}
}
// Finalize
void finalize() {
// Normalise to cross section
const double norm = crossSection()/picobarn/sumOfWeights();
scale( _h_DIS_dsigdzPom , norm);
scale( _h_DIS_dsigdlogXpom , norm);
scale( _h_DIS_dsigdW , norm);
scale( _h_DIS_dsigdQ2 , norm);
scale( _h_DIS_dsigdEtJet1 , norm);
scale( _h_DIS_dsigdAvgEta , norm);
scale( _h_DIS_dsigdDeltaEta, norm);
scale( _h_PHO_dsigdzPom , norm);
scale( _h_PHO_dsigdxGam , norm);
scale( _h_PHO_dsigdlogXpom , norm);
scale( _h_PHO_dsigdW , norm);
scale( _h_PHO_dsigdEtJet1 , norm);
scale( _h_PHO_dsigdAvgEta , norm);
scale( _h_PHO_dsigdDeltaEta, norm);
scale( _h_PHO_dsigdMjets , norm);
const double dPHO = nPHO;
MSG_INFO("H1_2007_I746380");
MSG_INFO("Cross section = " << crossSection()/picobarn << " pb");
MSG_INFO("Number of events = " << numEvents() << ", sumW = " << sumOfWeights());
MSG_INFO("Number of PHO = " << nPHO << ", number of DIS = " << nDIS);
MSG_INFO("Events passing electron veto = " << nVeto0 << " (" << nVeto0/dPHO * 100. << "%)" );
MSG_INFO("Events passing MY = " << nVeto1 << " (" << nVeto1/dPHO * 100. << "%)" );
MSG_INFO("Events passing t veto = " << nVeto2 << " (" << nVeto2/dPHO * 100. << "%)" );
MSG_INFO("Events passing xPom = " << nVeto3 << " (" << nVeto3/dPHO * 100. << "%)" );
MSG_INFO("Events passing jet Et veto = " << nVeto4 << " (" << nVeto4/dPHO * 100. << "%)" );
MSG_INFO("Events passing jet eta veto = " << nVeto5 << " (" << nVeto5/dPHO * 100. << "%)" );
}
//@}
private:
/// @name Histograms
//@{
// Book histograms from REF data
Histo1DPtr _h_DIS_dsigdzPom ;
Histo1DPtr _h_DIS_dsigdlogXpom ;
Histo1DPtr _h_DIS_dsigdW ;
Histo1DPtr _h_DIS_dsigdQ2 ;
Histo1DPtr _h_DIS_dsigdEtJet1 ;
Histo1DPtr _h_DIS_dsigdAvgEta ;
Histo1DPtr _h_DIS_dsigdDeltaEta;
Histo1DPtr _h_PHO_dsigdzPom ;
Histo1DPtr _h_PHO_dsigdxGam ;
Histo1DPtr _h_PHO_dsigdlogXpom ;
Histo1DPtr _h_PHO_dsigdW ;
Histo1DPtr _h_PHO_dsigdEtJet1 ;
Histo1DPtr _h_PHO_dsigdAvgEta ;
Histo1DPtr _h_PHO_dsigdDeltaEta;
Histo1DPtr _h_PHO_dsigdMjets ;
//@}
bool isDIS;
int nVeto0, nVeto1, nVeto2, nVeto3, nVeto4, nVeto5;
int nPHO, nDIS;
};
RIVET_DECLARE_PLUGIN(H1_2007_I746380);
}
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