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| CMS-HIN-23-007 ; CERN-EP-2024-118 | ||
| Pseudorapidity distributions of charged hadrons in lead-lead collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV | ||
| CMS Collaboration | ||
| 1 September 2024 | ||
| Submitted to Phys. Lett. B | ||
| Abstract: The pseudorapidity ($ \eta $) distributions of charged hadrons are measured using data collected at the highest ever nucleon-nucleon center-of-mass energy of $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV for collisions of lead-lead ions. The data were recorded by the CMS experiment at the LHC in 2022 and correspond to an integrated luminosity of 0.30 $ \pm $ 0.03 $ \mu$b$^{-1} $. Using the CMS silicon pixel detector, the yields of primary charged hadrons produced in the range $ |\eta| < $ 2.6 are reported. The evolution of the midrapidity particle density as a function of collision centrality is also reported. In the 5% most central collisions, the charged-hadron $ \eta $ density in the range $ |\eta| < $ 0.5 is found to be 2032 $ \pm $ 91 (syst), with negligible statistical uncertainty. This result is consistent with an extrapolation from nucleus-nucleus collision data at lower center-of-mass energies. Comparisons are made to various Monte Carlo event generators and to previous measurements of lead-lead and xenon-xenon collisions at similar collision energies. These new data detail the dependence of particle production on the collision energy, initial collision geometry, and the size of the colliding nuclei. | ||
| Links: e-print arXiv:2409.00838 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1:
The $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ distributions in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV for events in the 0$-$80% centrality class (left) and in the 0$-$5 and 50$-$55% centrality classes (right). The results have been averaged and symmetrized around $ \eta= $ 0. Predictions from the HYDJET 1.9 [16], AMPT 1.26t5 [35], and EPOS LHC v3400 event generators are also displayed. The ratios of the $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ distributions of simulation and data, normalized to unity at midrapidity, are shown in the bottom panel. The gray bands denote the total systematic uncertainties and the statistical uncertainties are negligible. In the ratio panels, the uncertainty band displayed represents the relative uncertainty of the data. |
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Figure 1-a:
The $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ distributions in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV for events in the 0$-$80% centrality class (left) and in the 0$-$5 and 50$-$55% centrality classes (right). The results have been averaged and symmetrized around $ \eta= $ 0. Predictions from the HYDJET 1.9 [16], AMPT 1.26t5 [35], and EPOS LHC v3400 event generators are also displayed. The ratios of the $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ distributions of simulation and data, normalized to unity at midrapidity, are shown in the bottom panel. The gray bands denote the total systematic uncertainties and the statistical uncertainties are negligible. In the ratio panels, the uncertainty band displayed represents the relative uncertainty of the data. |
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Figure 1-b:
The $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ distributions in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV for events in the 0$-$80% centrality class (left) and in the 0$-$5 and 50$-$55% centrality classes (right). The results have been averaged and symmetrized around $ \eta= $ 0. Predictions from the HYDJET 1.9 [16], AMPT 1.26t5 [35], and EPOS LHC v3400 event generators are also displayed. The ratios of the $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ distributions of simulation and data, normalized to unity at midrapidity, are shown in the bottom panel. The gray bands denote the total systematic uncertainties and the statistical uncertainties are negligible. In the ratio panels, the uncertainty band displayed represents the relative uncertainty of the data. |
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Figure 2:
Charged-hadron $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV at midrapidity as a function of event centrality, shown as is (left) and normalized by 2 $ A $ (right), where $ A $ is the atomic number of the nuclei. The results are compared to measurements in PbPb and XeXe collisions by the CMS [12,9] and ALICE [41,13,10] Collaborations, and to measurements in CuCu and AuAu collisions by the PHOBOS Collaboration [42]. The bands around the data points denote the total systematic uncertainties, while the statistical uncertainties are negligible. |
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Figure 2-a:
Charged-hadron $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV at midrapidity as a function of event centrality, shown as is (left) and normalized by 2 $ A $ (right), where $ A $ is the atomic number of the nuclei. The results are compared to measurements in PbPb and XeXe collisions by the CMS [12,9] and ALICE [41,13,10] Collaborations, and to measurements in CuCu and AuAu collisions by the PHOBOS Collaboration [42]. The bands around the data points denote the total systematic uncertainties, while the statistical uncertainties are negligible. |
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Figure 2-b:
Charged-hadron $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV at midrapidity as a function of event centrality, shown as is (left) and normalized by 2 $ A $ (right), where $ A $ is the atomic number of the nuclei. The results are compared to measurements in PbPb and XeXe collisions by the CMS [12,9] and ALICE [41,13,10] Collaborations, and to measurements in CuCu and AuAu collisions by the PHOBOS Collaboration [42]. The bands around the data points denote the total systematic uncertainties, while the statistical uncertainties are negligible. |
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Figure 3:
Average $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ at midrapidity normalized by $ \langle N_{\text{part}} \rangle $, shown as a function of $ \langle N_{\text{part}} \rangle $ (left) and $ \langle N_{\text{part}} \rangle/2A $ (right), where $ A $ is the atomic number of the nuclei. The results are compared to measurements in PbPb and XeXe collisions by the CMS [12,9], ALICE [41,13,10] Collaborations, and to measurements in CuCu and AuAu collisions by the PHOBOS Collaboration [42]. The bands around the data points denote the systematic uncertainties, while the statistical uncertainties are negligible. |
png pdf |
Figure 3-a:
Average $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ at midrapidity normalized by $ \langle N_{\text{part}} \rangle $, shown as a function of $ \langle N_{\text{part}} \rangle $ (left) and $ \langle N_{\text{part}} \rangle/2A $ (right), where $ A $ is the atomic number of the nuclei. The results are compared to measurements in PbPb and XeXe collisions by the CMS [12,9], ALICE [41,13,10] Collaborations, and to measurements in CuCu and AuAu collisions by the PHOBOS Collaboration [42]. The bands around the data points denote the systematic uncertainties, while the statistical uncertainties are negligible. |
png pdf |
Figure 3-b:
Average $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ at midrapidity normalized by $ \langle N_{\text{part}} \rangle $, shown as a function of $ \langle N_{\text{part}} \rangle $ (left) and $ \langle N_{\text{part}} \rangle/2A $ (right), where $ A $ is the atomic number of the nuclei. The results are compared to measurements in PbPb and XeXe collisions by the CMS [12,9], ALICE [41,13,10] Collaborations, and to measurements in CuCu and AuAu collisions by the PHOBOS Collaboration [42]. The bands around the data points denote the systematic uncertainties, while the statistical uncertainties are negligible. |
png pdf |
Figure 4:
Comparison of average $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ at midrapidity, scaled by $ \langle N_{\text{part}} \rangle $ in pPb [43,22], pAu [44], dAu [45,46,47] (pA) and central heavy ion collisions [12,42,48,49,50,8,51,52,53,41,54,46,55,56], as well as non-single-diffractive (NSD) [17,18,56,57,58,59] and inelastic [21,42,60,61] pp collisions. The data points for nucleus-nucleus (AA) collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 2.76 TeV have been shifted horizontally for visibility. The dashed curves, reproduced from Ref. [22], are included to guide the eye, and correspond to a power law functional form. |
| Tables | |
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Table 1:
Sources of systematic uncertainty affecting the measurement of charged-hadron multiplicities as a function of $ \langle N_{\text{part}} \rangle $ in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV. |
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Table 2:
Centrality intervals and corresponding $ \langle N_{\text{part}} \rangle $ values for 5.36 TeV PbPb collisions. The uncertainties in the $ N_{\text{part}} $ values are determined by propagating the uncertainties in the parameters of the Glauber model. |
| Summary |
| The pseudorapidity ($ \eta $) distributions of charged hadrons are measured in the range $ |\eta| < $ 2.6 for multiple centrality intervals using data collected in lead-lead (PbPb) collisions at the highest center-of-mass energy of $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.36 TeV. The dependence on $ \eta $ and centrality are compared to the event generators EPOS LHC v3400, HYDJET 1.9, and AMPT 1.26t5; none of these event generators are able to fully describe the measurements in terms of the magnitude, $ \eta $ dependence, and centrality dependence of the $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ distributions. In the 5% most central collisions, the charged-hadron density $ \mathrm{d} N_{\text{ch}}/\mathrm{d} \eta $ for the range $ |\eta| < $ 0.5 is found to be 2032 $ \pm $ 91 (syst), with negligible statistical uncertainty. The results at midrapidity are also compared to previous measurements in various collision systems, including PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 2.76 and 5.02 TeV, xenon-xenon collisions at 5.44 TeV, as well as copper-copper and gold-gold collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 200 GeV. These comparisons are new constraints on models and generators which describe multiparticle production in relativistic heavy ion collisions. |
| References | ||||
| 1 | W. Busza, K. Rajagopal, and W. van der Schee | Heavy ion collisions: The big picture, and the big questions | Ann. Rev. of Nucl. Part Sci. 68 (2018) 339 | 1802.04801 |
| 2 | P. Romatschke and U. Romatschke | Relativistic fluid dynamics in and out of equilibrium | Cambridge Monographs on Mathematical Physics. Cambridge University Press, ISBN~978-1-108-48368-1, 978-1-108-75002-8, 2019 link |
|
| 3 | J. L. Albacete and C. Marquet | Gluon saturation and initial conditions for relativistic heavy ion collisions | Prog. Part. Nucl. Phys. 76 (2014) 1 | 1401.4866 |
| 4 | D. Kharzeev and M. Nardi | Hadron production in nuclear collisions at RHIC and high density QCD | PLB 507 (2001) 121 | nucl-th/0012025 |
| 5 | D. d'Enterria et al. | Constraints from the first LHC data on hadronic event generators for ultra-high energy cosmic-ray physics | Astropart. Phys. 35 (2011) 98 | 1101.5596 |
| 6 | PHOBOS Collaboration | System size, energy and centrality dependence of pseudorapidity distributions of charged particles in relativistic heavy ion collisions | PRL 102 (2009) 142301 | 0709.4008 |
| 7 | PHOBOS Collaboration | Charged-particle pseudorapidity distributions in Au+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 62.4 GeV | PRC 74 (2006) 021901 | nucl-ex/0509034 |
| 8 | BRAHMS Collaboration | Pseudorapidity distributions of charged particles from Au+Au collisions at the maximum RHIC energy | PRL 88 (2002) 202301 | nucl-ex/0112001 |
| 9 | CMS Collaboration | Pseudorapidity distributions of charged hadrons in xenon-xenon collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}= $ 5.44 TeV | PLB 799 (2019) 135049 | CMS-HIN-17-006 1902.03603 |
| 10 | ALICE Collaboration | Centrality and pseudorapidity dependence of the charged-particle multiplicity density in Xe-Xe collisions at $ {\sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}} = $ 5.44 TeV | PLB 790 (2019) 35 | 1805.04432 |
| 11 | ALICE Collaboration | Centrality dependence of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}= $ 2.76 TeV | PRL 106 (2011) 032301 | 1012.1657 |
| 12 | CMS Collaboration | Dependence on pseudorapidity and on centrality of charged hadron production in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 2.76 TeV | JHEP 08 (2011) 141 | CMS-HIN-10-001 1107.4800 |
| 13 | ALICE Collaboration | Centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.02 TeV | PRL 116 (2016) 222302 | 1512.06104 |
| 14 | W.-T. Deng, X.-N. Wang, and R. Xu | Gluon shadowing and hadron production in heavy-ion collisions at LHC | PLB 701 (2011) 133 | 1011.5907 |
| 15 | T. Pierog et al. | EPOS LHC: Test of collective hadronization with data measured at the CERN Large Hadron Collider | PRC 92 (2015) 034906 | 1306.0121 |
| 16 | I. P. Lokhtin and A. M. Snigirev | A model of jet quenching in ultrarelativistic heavy ion collisions and high-$ p_{\mathrm{T}} $ hadron spectra at RHIC | EPJC 45 (2006) 211 | hep-ph/0506189 |
| 17 | CMS Collaboration | Transverse momentum and pseudorapidity distributions of charged hadrons in pp collisions at $ \sqrt{s} = $ 0.9 and 2.36 TeV | JHEP 02 (2010) 041 | CMS-QCD-09-010 1002.0621 |
| 18 | CMS Collaboration | Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at $ \sqrt{s}= $ 7 TeV | PRL 105 (2010) 022002 | CMS-QCD-10-006 1005.3299 |
| 19 | CMS Collaboration | Charged particle multiplicities in pp interactions at $ \sqrt{s} = $ 0.9, 2.36, and 7 TeV | JHEP 01 (2011) 079 | CMS-QCD-10-004 1011.5531 |
| 20 | CMS and TOTEM Collaborations | Measurement of pseudorapidity distributions of charged particles in proton-proton collisions at $ \sqrt{s} = $ 8 TeV by the CMS and TOTEM experiments | EPJC 74 (2014) 3053 | 1405.0722 |
| 21 | CMS Collaboration | Pseudorapidity distribution of charged hadrons in proton-proton collisions at $ \sqrt{s} = $ 13 TeV | PLB 751 (2015) 143 | CMS-FSQ-15-001 1507.05915 |
| 22 | CMS Collaboration | Pseudorapidity distributions of charged hadrons in proton-lead collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 5.02 and 8.16 TeV | JHEP 01 (2018) 045 | CMS-HIN-16-021 1710.09355 |
| 23 | CMS Collaboration | HEPData record for this analysis | link | |
| 24 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | |
| 25 | CMS Collaboration | CMS technical design report for the pixel detector upgrade | Technical Report, 2012 link |
|
| 26 | S. R. Klein et al. | STARlight: A Monte Carlo simulation program for ultra-peripheral collisions of relativistic ions | Comput. Phys. Commun. 212 (2017) 258 | 1607.03838 |
| 27 | S. Roesler, R. Engel, and J. Ranft | The Monte Carlo event generator DPMJET-III | Advanced Monte Carlo for radiation physics, particle transport simulation and applications. Lisbon, Portugal, 2000 link |
hep-ph/0012252 |
| 28 | K. Werner, F.-M. Liu, and T. Pierog | Parton ladder splitting and the rapidity dependence of transverse momentum spectra in deuteron-gold collisions at the BNL Relativistic Heavy Ion Collider | PRC 74 (2006) 044902 | hep-ph/0506232 |
| 29 | CMS Collaboration | Observation and studies of jet quenching in PbPb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 2.76 TeV | PRC 84 (2011) 024906 | CMS-HIN-10-004 1102.1957 |
| 30 | M. L. Miller, K. Reygers, S. J. Sanders, and P. Steinberg | Glauber modeling in high energy nuclear collisions | Ann. Rev. Nucl. Part. Sci. 57 (2007) 205 | nucl-ex/0701025 |
| 31 | C. Loizides, J. Kamin, and D. d'Enterria | Improved Monte Carlo Glauber predictions at present and future nuclear colliders | PRC 97 (2018) 054910 | 1710.07098 |
| 32 | C. M. Tarbert et al. | Neutron skin of $ ^{208} $Pb from coherent pion photoproduction | PRL 112 (2014) 242502 | 1311.0168 |
| 33 | C. Loizides, J. Nagle, and P. Steinberg | Improved version of the PHOBOS Glauber Monte Carlo | SoftwareX 1-2 (2014) 13 | 1408.2549 |
| 34 | GEANT4 Collaboration | GEANT 4---a simulation toolkit | NIM A 506 (2003) 250 | |
| 35 | Z.-W. Lin et al. | A multi-phase transport model for relativistic heavy ion collisions | PRC 72 (2005) 064901 | nucl-th/0411110 |
| 36 | V. N. Gribov | A Reggeon diagram technique | Sov. Phys. JETP 26 (1968) 414 | |
| 37 | H. J. Drescher et al. | Parton based Gribov-Regge theory | Phys. Rept. 350 (2001) 93 | hep-ph/0007198 |
| 38 | X.-N. Wang and M. Gyulassy | HIJING: A Monte Carlo model for multiple jet production in pp, pA and AA collisions | PRD 44 (1991) 3501 | |
| 39 | B. Zhang | ZPC 1.0.1: A parton cascade for ultrarelativistic heavy ion collisions | Comput. Phys. Commun. 109 (1998) 193 | nucl-th/9709009 |
| 40 | B.-A. Li and C. M. Ko | Formation of superdense hadronic matter in high energy heavy-ion collisions | PRC 52 (1995) 2037 | nucl-th/9505016 |
| 41 | ALICE Collaboration | Charged-particle multiplicity density at midrapidity in central Pb-Pb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 2.76 TeV | PRL 105 (2010) 252301 | 1011.3916 |
| 42 | PHOBOS Collaboration | Phobos results on charged particle multiplicity and pseudorapidity distributions in Au+Au, Cu+Cu, d+Au, and p+p collisions at ultra-relativistic energies | PRC 83 (2011) 024913 | 1011.1940 |
| 43 | ALICE Collaboration | Pseudorapidity density of charged particles in p+Pb collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}= $ 5.02 TeV | PRL 110 (2013) 032301 | 1210.3615 |
| 44 | NA35 Collaboration | Charged particle production in proton-, deuteron-, oxygen- and sulphur-nucleus collisions at 200 GeV per nucleon | EPJC 2 (1998) 643 | hep-ex/9711001 |
| 45 | PHOBOS Collaboration | Pseudorapidity distribution of charged particles in d+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 200 GeV | PRL 93 (2004) 082301 | nucl-ex/0311009 |
| 46 | PHENIX Collaboration | Transverse energy production and charged-particle multiplicity at midrapidity in various systems from $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}= $ 7.7 to 200 GeV | PRC 93 (2016) 024901 | 1509.06727 |
| 47 | PHENIX Collaboration | Measurements of azimuthal anisotropy and charged-particle multiplicity in d+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 200, 62.4, 39, and 19.6 GeV | PRC 96 (2017) 064905 | 1708.06983 |
| 48 | NA50 Collaboration | Scaling of charged particle multiplicity in PbPb collisions at SPS energies | PLB 530 (2002) 43 | |
| 49 | STAR Collaboration | Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 130 GeV | PRL 87 (2001) 112303 | nucl-ex/0106004 |
| 50 | BRAHMS Collaboration | Charged particle densities from Au+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 130 GeV | PLB 523 (2001) 227 | nucl-ex/0108016 |
| 51 | PHENIX Collaboration | Centrality dependence of charged particle multiplicity in Au-Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 130 GeV | PRL 86 (2001) 3500 | nucl-ex/0012008 |
| 52 | PHOBOS Collaboration | Charged-particle multiplicity near midrapidity in central Au+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 56 and 130 GeV | PRL 85 (2000) 3100 | hep-ex/0007036 |
| 53 | PHOBOS Collaboration | Charged-particle pseudorapidity density distributions from Au+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 130 GeV | PRL 87 (2001) 102303 | nucl-ex/0106006 |
| 54 | ATLAS Collaboration | Measurement of the centrality dependence of the charged particle pseudorapidity distribution in lead-lead collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}= $ 2.76 TeV with the ATLAS detector | PLB 710 (2012) 363 | 1108.6027 |
| 55 | STAR Collaboration | Identified particle production, azimuthal anisotropy, and interferometry measurements in Au+Au collisions at $ \sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = $ 9.2 GeV | PRC 81 (2010) 024911 | 0909.4131 |
| 56 | STAR Collaboration | Systematic measurements of identified particle spectra in pp, d+Au and Au+Au collisions from STAR | PRC 79 (2009) 034909 | 0808.2041 |
| 57 | UA1 Collaboration | A study of the general characteristics of $ \mathrm{p}\bar{\mathrm{p}} $ collisions at $ \sqrt{s} = $ 0.2 TeV to 0.9 TeV | NPB 335 (1990) 261 | |
| 58 | UA5 Collaboration | Particle multiplicities in $ \mathrm{p}\bar{\mathrm{p}} $ interactions at $ \sqrt{s} = $ 540 GeV | PLB 121 (1983) 209 | |
| 59 | CDF Collaboration | Pseudorapidity distributions of charged particles produced in $ \bar{\mathrm{p}} \mathrm{p} $ interactions at $ \sqrt{s} = $ 630 GeV and 1800 GeV | PRD 41 (1990) 2330 | |
| 60 | Aachen-CERN-Heidelberg-Munich Collaboration | Charged particle multiplicity distributions in pp collisions at ISR Energies | NPB 129 (1977) 365 | |
| 61 | ALICE Collaboration | Charged-particle multiplicity measurement in proton-proton collisions at $ \sqrt{s}= $ 0.9 and 2.36 TeV with ALICE at LHC | EPJC 68 (2010) 89 | 1004.3034 |
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