Rivet analyses
Enhanced production of multi-strange hadrons in high-multiplicity proton-proton collisions.
Experiment: ALICE (LHC)
Inspire ID: 1471838
Status: UNVALIDATED
Authors: - Christian Bierlich
References: - Nature.Phys.13(2017)535-539 - arXiv: 1606.07424
Beams: p+ p+
Beam energies: (3500.0, 3500.0)GeV
Run details: - Minimum bias pp
Measurements of pT spectra and yields of (multi)strange hadrons, as well as protons and pions (yields only) in forward multiplicity classes at 7 TeV. Ratios of yields to pion yields are constructed. The analysis takes care of particle reconstruction as the experiment does, so no finite lifetime should be imposed on generator level. Experimental results are scaled to inelastic cross section, and generator setup should be adjusted accordingly.
Source
code:ALICE_2016_I1471838.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/CentralityProjection.hh"
#include "Rivet/Analyses/AliceCommon.hh"
namespace Rivet {
/// @brief Strangeness enhancement in pp 7 TeV by ALICE.
class ALICE_2016_I1471838 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2016_I1471838);
int profileIndex(vector<double> cBins, double c) {
int index = 100;
if (c > 0 && c <= cBins[0]) return cBins.size() - 1;
for (size_t i = 0; i < cBins.size() - 1; ++i) {
if (c > cBins[i] && c <= cBins[i + 1]) {
index = i;
break;
}
}
return max(0, int(cBins.size() - index - 2));
}
/// Book histograms and initialise projections before the run
void init() {
// Centrality projection.
declareCentrality(ALICE::V0MMultiplicity(),
"ALICE_2015_CENT_PP","V0M","V0M");
// Central primary particles
declare(ChargedFinalState(Cuts::abseta < 1.0),"PP");
declare(ALICE::PrimaryParticles(Cuts::absrap < 0.5),"PPy");
centralityBins = {1.,5.,10.,15.,20., 30., 40., 50., 70., 100.};
centralityBinsOmega = {5.,15.,30.,50.,100.};
// Book histograms
for (int i = 0; i < 10; ++i) {
book(K0SpT[centralityBins[i]], i+1,1,1);
book(LambdapT[centralityBins[i]], i+11,1,1);
book(XipT[centralityBins[i]], i+21,1,1);
book(sow[centralityBins[i]], "sow_" + toString(i));
}
for (int i = 0; i < 5; ++i) {
book(OmegapT[centralityBinsOmega[i]], i+31,1,1);
book(sowOmega[centralityBinsOmega[i]], "sowO_" + toString(i));
}
book(piYield, 40,1,1);
book(pYield, 41,1,1);
book(kYield, 42,1,1);
book(lambdaYield, 43,1,1);
book(xiYield, 44,1,1);
book(omegaYield, 45,1,1);
book(piRebinned, "/piRebinned", refData(45,1,1));
// Make the ratios
book(kpi, 36, 1, 1);
book(ppi, 47, 1, 1);
book(lpi, 37, 1, 1);
book(xpi, 38, 1, 1);
book(opi, 39, 1, 1);
book(lk, 46, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
if (apply<ChargedFinalState>(event,"PP").particles().size() < 1) vetoEvent;
const ALICE::PrimaryParticles& prim = apply<ALICE::PrimaryParticles>(event,"PPy");
const CentralityProjection& cent = apply<CentralityProjection>(event,"V0M");
double c = cent();
// Find the correct histograms
auto kptItr = K0SpT.upper_bound(c);
if (kptItr == K0SpT.end()) return;
auto lptItr = LambdapT.upper_bound(c);
if (lptItr == LambdapT.end()) return;
auto xptItr = XipT.upper_bound(c);
if (xptItr == XipT.end()) return;
auto optItr = OmegapT.upper_bound(c);
if (optItr == OmegapT.end()) return;
// Fill the sow.
auto sowItr = sow.upper_bound(c);
if (sowItr == sow.end()) return;
auto sowOmegaItr = sowOmega.upper_bound(c);
if (sowOmegaItr == sowOmega.end()) return;
sowItr->second->fill();
sowOmegaItr->second->fill();
// Fill the pt histograms and count yields.
int npi = 0, npr = 0, nk = 0;
int nla = 0, nxi = 0, nom = 0;
for (auto p : prim.particles()) {
const double pT = p.pT();
const int pid = abs(p.pid());
if (pid == 211) ++npi;
else if (pid == 2212) ++npr;
else if (pid == 310) {
kptItr->second->fill(pT);
++nk;
}
else if (pid == 3122) {
lptItr->second->fill(pT);
++nla;
}
else if (pid == 3312) {
xptItr->second->fill(pT);
++nxi;
}
else if (pid == 3334) {
optItr->second->fill(pT);
++nom;
}
}
// Fill the profiles of yields.
int index = profileIndex(centralityBins,c);
piYield->fill(piYield->bin(index).xMid(), double(npi));
pYield->fill(pYield->bin(index).xMid(), double(npr));
kYield->fill(kYield->bin(index).xMid(), double(nk));
lambdaYield->fill(lambdaYield->bin(index).xMid(), double(nla));
xiYield->fill(xiYield->bin(index).xMid(), double(nxi));
index = profileIndex(centralityBinsOmega, c);
omegaYield->fill(omegaYield->bin(index).xMid(), double(nom));
piRebinned->fill(piRebinned->bin(index).xMid(),double(npi));
}
/// Normalise histograms etc., after the run
void finalize() {
// Normalize the spectra
for (int i = 0; i < 10; ++i) {
K0SpT[centralityBins[i]]->scaleW(1./sow[centralityBins[i]]->sumW());
XipT[centralityBins[i]]->scaleW(1./sow[centralityBins[i]]->sumW());
LambdapT[centralityBins[i]]->scaleW(1./sow[centralityBins[i]]->sumW());
}
for (int i = 0; i < 5; ++i) {
OmegapT[centralityBinsOmega[i]]->scaleW(1./sowOmega[centralityBinsOmega[i]]->sumW());
}
divide(kYield, piYield, kpi);
kpi->scale(2.);
divide(pYield, piYield, ppi);
divide(lambdaYield, piYield, lpi);
divide(xiYield, piYield, xpi);
divide(omegaYield, piRebinned, opi);
divide(lambdaYield, kYield, lk);
lk->scale(0.5);
}
/// @}
/// @name Histograms
/// @{
// Histograms ordered in centrality classes
vector<double> centralityBins;
vector<double> centralityBinsOmega;
// pT spectra
map<double, Histo1DPtr> K0SpT;
map<double, Histo1DPtr> LambdapT;
map<double, Histo1DPtr> XipT;
map<double, Histo1DPtr> OmegapT;
map<double, CounterPtr> sow;
map<double, CounterPtr> sowOmega;
// Total yields
Profile1DPtr piYield;
Profile1DPtr pYield;
Profile1DPtr kYield;
Profile1DPtr lambdaYield;
Profile1DPtr xiYield;
Profile1DPtr omegaYield;
Profile1DPtr piRebinned;
// Ratios
Estimate1DPtr kpi;
Estimate1DPtr ppi;
Estimate1DPtr lpi;
Estimate1DPtr xpi;
Estimate1DPtr opi;
Estimate1DPtr lk;
/// @}
};
RIVET_DECLARE_PLUGIN(ALICE_2016_I1471838);
}