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ALICE_2021_I1862793

Prompt $\Xi_{c}^{0}$ and $\Xi_{c}^{+}$ analysis
Experiment: ALICE (LHC)
Inspire ID: 1862793
Status: VALIDATED
Authors:
  • Yonne Lourens
References:
  • Phys. Rev. Lett. 127 (2021) 272001
  • DOI:10.1103/PhysRevLett.127.272001
  • arXiv: 2105.05187
  • Public page: ALICE-7074
Beams: p+ p+
Beam energies: (6500.0, 6500.0) GeV
Run details:
  • Minimum bias events

The $p_\text{T}$-differential cross sections of prompt charm-strange baryons $\Xi^0_{c}$ and $\Xi^+_{c}$ were measured at midrapidity ($|y| < 0.5$) in proton--proton (pp) collisions at a centre-of-mass energy $\sqrt{s}=$ 13 TeV with the ALICE detector at the LHC. The $\Xi^0_{c}$ baryon was reconstructed via both the semileptonic decay ($\Xi^{-}{e^{+}}\nu_{e}$) and the hadronic decay ($\Xi^{-}{\pi^{+}}$) channels. The $\Xi^+_{c}$ baryon was reconstructed via the hadronic decay ($\Xi^{-}\pi^{+}\pi^{+}$) channel. The branching-fraction ratio ${BR}(\Xi_c^0\rightarrow \Xi^-e^+\nu_e)/{\rm BR}(\Xi_c^0\rightarrow \Xi^{-}\pi^+)=$ 1.38 $\pm$ 0.14 (stat) $\pm$ 0.22 (syst) was measured with a total uncertainty reduced by a factor of about 3 with respect to the current world average reported by the Particle Data Group. The transverse momentum ($p_\text{T}$) dependence of the $\Xi^0_{c}$- and $\Xi^+_{c}$-baryon production relative to the ${D^0}$-meson and to the $\Sigma^{0,+,++}_{c}$- and $\Lambda^+_{c}$-baryon production are reported. The baryon-to-meson ratio increases towards low $p_\text{T}$ up to a value of approximately 0.3. The measurements are compared with various models that take different hadronisation mechanisms into consideration. The results provide stringent constraints to these theoretical calculations and additional evidence that different processes are involved in charm hadronisation in electron--positron ($e^+e^-$) and hadronic collisions.

Source code: ALICE_2021_I1862793.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/UnstableParticles.hh"
  4
  5namespace Rivet {
  6
  7  /// @brief Prompt charm-strange baryons in pp at 13 TeV
  8  class ALICE_2021_I1862793 : public Analysis {
  9  public:
 10
 11    RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2021_I1862793);
 12
 13    void init() {
 14
 15      const UnstableParticles up(Cuts::absrap < 0.5);
 16      declare(up, "up");
 17
 18      book(_h_X0,1,1,1);                                     // XiC0 production cross section
 19      book(_h_XP,2,1,1);                                     // XiC+ production cross section
 20      book(_h_X0D0,3,1,1);                                   // ratio of production cross section between XiC0 and D0
 21      book(_h_XPDP,4,1,1);                                   // ratio of production cross section between XiC+ and D0
 22      book(_h_X0Lc,5,1,1);                                   // ratio of production cross section between XiC and LambdaC
 23      book(_h_XcSc,6,1,1);                                   // ratio of production cross section between XiC and SigmaC
 24      book(_h_X0Iint,"TMP/Xint", refData(7,1,1));            // XiC0 pt-integrated production cross section with 1<pt<12 GeV/c
 25      book(_h_X0Oint,8,1,1);                                 // XiC0 pt-integrated production cross section with pt>0 GeV/c
 26      book(_h_XPint,9,1,1);                                  // XiC+ pt-integrated production cross section with 4<pt<12 GeV/c
 27
 28
 29      book(_h_X0D,"TMP/_h_X0D",refData(3,1,1));              // XiC0 production cross section
 30      book(_h_D0,"TMP/_h_D0",refData(3,1,1));                // D0 production cross section
 31
 32      book(_h_DP,"TMP/_h_DP",refData(4,1,1));                // D0 production cross section
 33      book(_h_XPD,"TMP/_h_XPD",refData(4,1,1));              // XiC+ production cross section
 34
 35      book(_h_Lc,"TMP/_h_Lc",refData(5,1,1));                // LambdaC production cross section
 36      book(_h_X0L,"TMP/_h_X0L",refData(5,1,1));              // XiC0 production cross section
 37
 38      book(_h_Sc,"TMP/_h_Sc",refData(6,1,1));                // SigmaC production cross section
 39      book(_h_Xc,"TMP/_h_Xc",refData(6,1,1));                // XiC production cross section
 40
 41
 42    }
 43
 44
 45    void analyze(const Event& event) {
 46      if(_edges.empty()) _edges=_h_X0Oint->xEdges();
 47      const UnstableParticles& up = apply<UnstableParticles>(event, "up");
 48
 49      for (const Particle& p : up.particles()) {
 50        if(p.fromBottom())
 51          continue;
 52
 53        else{
 54          if(p.abspid() == 4222 || p.abspid() == 4212 || p.abspid() == 4112){
 55            _h_Sc->fill(p.pT()/GeV);
 56          }
 57
 58          else if(p.abspid() == 4122){
 59            _h_Lc->fill(p.pT()/GeV);
 60          }
 61
 62          else if(p.abspid() == 421){
 63            _h_D0->fill(p.pT()/GeV);
 64            _h_DP->fill(p.pT()/GeV);
 65          }
 66
 67          else if(p.abspid() == 4132){
 68            _h_X0->fill(p.pT()/GeV);
 69            _h_X0D->fill(p.pT()/GeV);
 70            _h_Xc->fill(p.pT()/GeV);
 71            _h_X0L->fill(p.pT()/GeV);
 72            _h_X0Oint->fill(_edges[0]);
 73
 74            if(p.pT()/GeV < 12.0 && p.pT()/GeV >= 1.0){
 75              _h_X0Iint->fill(1);
 76            }
 77
 78          }
 79
 80          else if(p.abspid() == 4232){
 81            _h_XP->fill(p.pT()/GeV);
 82            _h_Xc->fill(p.pT()/GeV);
 83            _h_XPD->fill(p.pT()/GeV);
 84
 85             if(p.pT()/GeV < 12.0 && p.pT()/GeV >= 4.0){
 86              _h_XPint->fill(8);
 87            }
 88          }
 89        }
 90      }
 91    }
 92
 93    void finalize() {
 94
 95      scale(_h_Sc,              crossSection()/(microbarn*2*sumOfWeights()));
 96      scale(_h_Lc,              crossSection()/(microbarn*2*sumOfWeights()));
 97      scale(_h_D0,              crossSection()/(microbarn*2*sumOfWeights()));
 98      scale(_h_DP,              crossSection()/(microbarn*2*sumOfWeights()));
 99
100      scale(_h_Xc,              crossSection()/(microbarn*2*sumOfWeights()));
101      scale(_h_X0,              crossSection()/(microbarn*2*sumOfWeights()));
102      scale(_h_XP,              crossSection()/(microbarn*2*sumOfWeights()));
103
104      scale(_h_X0D,              crossSection()/(microbarn*2*sumOfWeights()));
105      scale(_h_XPD,              crossSection()/(microbarn*2*sumOfWeights()));
106      scale(_h_X0L,              crossSection()/(microbarn*2*sumOfWeights()));
107
108      divide(_h_X0D, _h_D0, _h_X0D0);
109      divide(_h_XPD, _h_DP, _h_XPDP);
110      divide(_h_X0L, _h_Lc, _h_X0Lc);
111      divide(_h_Xc, _h_Sc, _h_XcSc);
112
113      scale(_h_X0Iint,              crossSection()/(microbarn*2*sumOfWeights()));
114      Estimate1DPtr tmp;
115      book(tmp,7,1,1);
116      barchart(_h_X0Iint,tmp);
117      scale(_h_X0Oint,              crossSection()/(microbarn*2*sumOfWeights()));
118      scale(_h_XPint,               crossSection()/(microbarn*2*sumOfWeights()));
119
120    }
121
122    Histo1DPtr _h_X0, _h_XP, _h_X0Iint, _h_XPint, _h_Sc, _h_Lc, _h_D0, _h_DP, _h_Xc, _h_X0D, _h_XPD, _h_X0L;
123    Estimate1DPtr _h_X0D0, _h_XPDP, _h_X0Lc, _h_XcSc;
124    BinnedHistoPtr<string> _h_X0Oint;
125    vector<string> _edges;
126
127  };
128
129
130  RIVET_DECLARE_PLUGIN(ALICE_2021_I1862793);
131
132}