Rivet analyses
Charm hadron differential cross-sections in p⟂ and rapidity at $\sqrt{s} = 5$ TeV
Experiment: LHCB (LHC 5TeV)
Inspire ID: 1490663
Status: VALIDATED
Authors: - Dominik Muller - Patrick Spradlin
References: - JHEP 1706 (2017) 147 - doi JHEP 1706 (2017) 147 - arXiv 1610.02230 [hep-ex] - CERN-EP-2016-244, LHCB-PAPER-2016-042
Beams: p+ p+
Beam energies: (2510.0, 2510.0)GeV
Run details: - Minimum bias QCD events, proton–proton interactions at $\sqrt{s} = 5$ TeV.
Measurements of differential production cross-sections with respect to transverse momentum, dσ(Hc + c.c.)/dpT, for charm hadron species Hc ∈ {D0, D+, D*(2010)+, Ds+} in proton–proton collisions at center-of-mass energy $\sqrt{s}= 5$ TeV. The differential cross-sections are measured in bins of hadron transverse momentum (pT) and rapidity (y) with respect to the beam axis in the region 0 < pT < 10 GeV/c and 2.0 < y < 4.5, where pT and y are measured in the proton–proton CM frame. In this analysis code, it is assumed that the event coordinate system is in the proton–proton CM frame with the z-axis corresponding to the proton–proton collision axis (as usual). Contributions of charm hadrons from the decays of b-hadrons and other particles with comparably large mean lifetimes have been removed in the measurement. In this analysis code, this is implemented by counting only charm hadrons that do not have an ancestor that contains a b quark.
Source
code:LHCB_2016_I1490663.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// LHCb prompt charm hadron pT and rapidity spectra
class LHCB_2016_I1490663 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2016_I1490663);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
/// Initialise and register projections
declare(UnstableParticles(), "UFS");
/// Book histograms
book(_h_pdg411_Dplus_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
book(_h_pdg421_Dzero_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
book(_h_pdg431_Dsplus_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
book(_h_pdg413_Dstarplus_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
for (size_t i = 1; i < _h_pdg411_Dplus_pT_y->numBins()+1; ++i) {
size_t y = _h_pdg411_Dplus_pT_y->bin(i).index();
book(_h_pdg411_Dplus_pT_y->bin(i), 1, 1, y);
book(_h_pdg421_Dzero_pT_y->bin(i), 2, 1, y);
book(_h_pdg431_Dsplus_pT_y->bin(i), 3, 1, y);
book(_h_pdg413_Dstarplus_pT_y->bin(i), 4, 1, y);
}
book(_hbr_Dzero, {2., 2.5, 3., 3.5, 4., 4.5});
book(_hbr_Dplus, {2., 2.5, 3., 3.5, 4., 4.5});
book(_hbr_Ds, {2., 2.5, 3., 3.5, 4., 4.5});
book(_hbr_Dstar, {2., 2.5, 3., 3.5, 4., 4.5});
for (size_t i = 1; i < _hbr_Dzero->numBins()+1; ++i) {
book(_hbr_Dzero->bin(i), "TMP/Dzero_b"+to_str(i), refData(9, 1, 2));
book(_hbr_Dplus->bin(i), "TMP/Dplus_b"+to_str(i), refData(9, 1, 2));
book(_hbr_Ds->bin(i), "TMP/Ds_b"+to_str(i), refData(9, 1, 2));
book(_hbr_Dstar->bin(i), "TMP/Dstar_b"+to_str(i), refData(9, 1, 2));
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
/// @todo Use PrimaryHadrons to avoid double counting and automatically remove the contributions from unstable?
const UnstableParticles &ufs = apply<UnstableParticles> (event, "UFS");
for (const Particle& p : ufs.particles() ) {
// We're only interested in charm hadrons
//if (!p.isHadron() || !p.hasCharm()) continue;
PdgId apid = p.abspid();
// do not use Cuts::abspid to avoid supplemental iteration on particles?
if ((apid != 411) && (apid != 421) && (apid != 431) && (apid != 413)) continue;
// Experimental selection removes non-prompt charm hadrons: we ignore those from b decays
if (p.fromBottom()) continue;
// Kinematic acceptance
const double y = p.absrap(); ///< Double analysis efficiency with a "two-sided LHCb"
const double pT = p.pT()/GeV;
// Fiducial acceptance of the measurements
if ((pT > 10.0) || (y < 2.0) || (y > 4.5)) continue;
Particles daus;
switch (apid) {
case 411:
_h_pdg411_Dplus_pT_y->fill(y, pT);
// veto on decay channel [D+ -> K- pi+ pi+]cc
if (p.children().size() != 3) break;
if ( ((p.children(Cuts::pid == -321).size() == 1) && (p.children(Cuts::pid == 211).size() == 2)) ||
((p.children(Cuts::pid == 321).size() == 1) && (p.children(Cuts::pid == -211).size() == 2)) )
_hbr_Dplus->fill(y, pT); // MSG_INFO("Found [ D+ -> K- pi+ pi+ ]cc..."); };
break;
case 421:
_h_pdg421_Dzero_pT_y->fill(y, pT);
// veto on decay channel [D0 -> K- pi+]cc
if (p.children().size() != 2) break;
if ( ((p.children(Cuts::pid == -321).size() == 1) && (p.children(Cuts::pid == 211).size() == 1)) ||
((p.children(Cuts::pid == 321).size() == 1) && (p.children(Cuts::pid == -211).size() == 1)) )
_hbr_Dzero->fill(y, pT); // MSG_INFO("Found [ D0 -> K- pi+ ]cc..."); };
break;
case 431:
_h_pdg431_Dsplus_pT_y->fill(y, pT);
//veto on decay channel [Ds+ -> [K+ K-]phi0 pi+]cc
if (p.children().size() != 2) break;
daus = p.children(Cuts::pid == 333);
if ( (daus.size() == 1) && (p.children(Cuts::abspid == 211).size() == 1) &&
(daus.front().children(Cuts::abspid ==321).size() == 2) )
_hbr_Ds->fill(y, pT); // MSG_INFO("Found [ Ds+ -> phi0(-> K+ K-) pi+ ]cc..."); };
break;
case 413:
_h_pdg413_Dstarplus_pT_y->fill(y, pT);
// veto on decay channel [D*+ -> [K- pi+]D0 pi+]cc
if (p.children().size() != 2) break;
daus = p.children(Cuts::pid == 421);
if ( (daus.size() == 1) && (p.children(Cuts::abspid == 211).size() == 1) &&
( daus.front().children().size() == 2 ) &&
( ( (daus.front().children(Cuts::pid == -321).size() == 1 ) && (daus.front().children(Cuts::pid == 211).size() == 1 ) ) ||
( (daus.front().children(Cuts::pid == 321).size() == 1 ) && (daus.front().children(Cuts::pid == -211).size() == 1 ) ) ) )
_hbr_Dstar->fill(y, pT); // MSG_INFO("Found [ D*+ -> D0 (-> K- pi+)cc pi+ ]cc..."); };
break;
default:
break;
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
/// Factor of 0.5 to correct for the abs(rapidity) used above
const double scale_factor = 0.5 * crossSection()/microbarn / sumOfWeights();
scale(_h_pdg411_Dplus_pT_y, scale_factor);
scale(_h_pdg421_Dzero_pT_y, scale_factor);
scale(_h_pdg431_Dsplus_pT_y, scale_factor);
scale(_h_pdg413_Dstarplus_pT_y, scale_factor);
// Do ratios
for (int i = 0; i < 5; ++i) {
book(hr_DplusDzero[i], 9, 1, i+1);
book(hr_DsDzero[i], 10, 1, i+1);
book(hr_DstarDzero[i], 11, 1, i+1);
book(hr_DsDplus[i], 12, 1, i+1);
book(hr_DstarDplus[i], 13, 1, i+1);
book(hr_DsDstar[i], 14, 1, i+1);
divide(_hbr_Dplus->bin(i+1), _hbr_Dzero->bin(i+1), hr_DplusDzero[i]);
divide(_hbr_Ds->bin(i+1), _hbr_Dzero->bin(i+1), hr_DsDzero[i]);
divide(_hbr_Dstar->bin(i+1), _hbr_Dzero->bin(i+1), hr_DstarDzero[i]);
divide(_hbr_Ds->bin(i+1), _hbr_Dplus->bin(i+1), hr_DsDplus[i]);
divide(_hbr_Dstar->bin(i+1), _hbr_Dplus->bin(i+1), hr_DstarDplus[i]);
divide(_hbr_Ds->bin(i+1), _hbr_Dstar->bin(i+1), hr_DsDstar[i]);
// scale 100x as measurement is in %
hr_DplusDzero[i]->scale(100.);
hr_DsDzero[i]->scale(100.);
hr_DstarDzero[i]->scale(100.);
hr_DsDplus[i]->scale(100.);
hr_DstarDplus[i]->scale(100.);
hr_DsDstar[i]->scale(100.);
}
}
/// @}
private:
/// @name Histograms
/// @{
Histo1DGroupPtr _h_pdg411_Dplus_pT_y, _hbr_Dplus;
Histo1DGroupPtr _h_pdg421_Dzero_pT_y, _hbr_Dzero;
Histo1DGroupPtr _h_pdg431_Dsplus_pT_y, _hbr_Ds;
Histo1DGroupPtr _h_pdg413_Dstarplus_pT_y, _hbr_Dstar;
Estimate1DPtr hr_DplusDzero[5];
Estimate1DPtr hr_DsDzero[5];
Estimate1DPtr hr_DstarDzero[5];
Estimate1DPtr hr_DsDplus[5];
Estimate1DPtr hr_DstarDplus[5];
Estimate1DPtr hr_DsDstar[5];
/// @}
};
RIVET_DECLARE_PLUGIN(LHCB_2016_I1490663);
}