Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at root S-NN=8.16 TeV

The ALICE Collaboration, S. Acharya, E. J. Brucken, B. Chang, T. E. Hilden, D. J. Kim, V. Litichevskyi, M. M. Mieskolainen, R. Orava, J. E. Parkkila, J. Rak, S. S. Räsänen, S. Saarinen, M. Slupecki, T. W. Snellman, W. H. Trzaska, M. Vargyas, J. Viinikainen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The pseudorapidity density of charged particles, dN(ch)/d eta, in p-Pb collisions has been measured at a centre of-mass energy per nucleon-nucleon pair of root S-NN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, vertical bar eta vertical bar < 1.8. The dN(ch)/d eta value is 19.1 +/- 0.7 at vertical bar eta vertical bar < 0.5. This quantity divided by < N-part >/2 is 4.73 +/- 0.20, where < N-part > is the average number of participating nucleons, is 9.5% higher than the corresponding value for p-Pb collisions at root S-NN = 5.02 TeV. Measurements are compared with models based on different mechanisms for particle production. All models agree within uncertainties with data in the Pb-going side, while HIJING overestimates, showing a symmetric behaviour, and EPOS underestimates the p-going side of the dN(ch)/d eta distribution. Saturation-based models reproduce the distributions well for eta > -1.3. The dN(ch)/d eta is also measured for different centrality estimators, based both on the charged particle multiplicity and on the energy deposited in the Zero Degree Calorimeters. A study of the implications of the large multiplicity fluctuations due to the small number of participants for systems like p-Pb in the centrality calculation for multiplicity-based estimators is discussed, demonstrating the advantages of determining the centrality with energy deposited near beam rapidity.
Original languageEnglish
Article number307
JournalEuropean Physical Journal C. Particles and Fields
Volume79
Issue number4
Number of pages17
ISSN1434-6044
DOIs
Publication statusPublished - 4 Apr 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences
  • AU COLLISIONS
  • MULTIPLICITY
  • DISTRIBUTIONS
  • DEPENDENCE
  • CENTRALITY

Cite this

The ALICE Collaboration ; Acharya, S. ; Brucken, E. J. ; Chang, B. ; Hilden, T. E. ; Kim, D. J. ; Litichevskyi, V. ; Mieskolainen, M. M. ; Orava, R. ; Parkkila, J. E. ; Rak, J. ; Räsänen, S. S. ; Saarinen, S. ; Slupecki, M. ; Snellman, T. W. ; Trzaska, W. H. ; Vargyas, M. ; Viinikainen, J. / Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at root S-NN=8.16 TeV. In: European Physical Journal C. Particles and Fields. 2019 ; Vol. 79, No. 4.
@article{c7f2470aa3364fd9a6c7fc6adffde66a,
title = "Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at root S-NN=8.16 TeV",
abstract = "The pseudorapidity density of charged particles, dN(ch)/d eta, in p-Pb collisions has been measured at a centre of-mass energy per nucleon-nucleon pair of root S-NN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, vertical bar eta vertical bar < 1.8. The dN(ch)/d eta value is 19.1 +/- 0.7 at vertical bar eta vertical bar < 0.5. This quantity divided by < N-part >/2 is 4.73 +/- 0.20, where < N-part > is the average number of participating nucleons, is 9.5{\%} higher than the corresponding value for p-Pb collisions at root S-NN = 5.02 TeV. Measurements are compared with models based on different mechanisms for particle production. All models agree within uncertainties with data in the Pb-going side, while HIJING overestimates, showing a symmetric behaviour, and EPOS underestimates the p-going side of the dN(ch)/d eta distribution. Saturation-based models reproduce the distributions well for eta > -1.3. The dN(ch)/d eta is also measured for different centrality estimators, based both on the charged particle multiplicity and on the energy deposited in the Zero Degree Calorimeters. A study of the implications of the large multiplicity fluctuations due to the small number of participants for systems like p-Pb in the centrality calculation for multiplicity-based estimators is discussed, demonstrating the advantages of determining the centrality with energy deposited near beam rapidity.",
keywords = "114 Physical sciences, AU COLLISIONS, MULTIPLICITY, DISTRIBUTIONS, DEPENDENCE, CENTRALITY",
author = "{The ALICE Collaboration} and S. Acharya and Brucken, {E. J.} and B. Chang and Hilden, {T. E.} and Kim, {D. J.} and V. Litichevskyi and Mieskolainen, {M. M.} and R. Orava and Parkkila, {J. E.} and J. Rak and R{\"a}s{\"a}nen, {S. S.} and S. Saarinen and M. Slupecki and Snellman, {T. W.} and Trzaska, {W. H.} and M. Vargyas and J. Viinikainen",
year = "2019",
month = "4",
day = "4",
doi = "10.1140/epjc/s10052-019-6801-9",
language = "English",
volume = "79",
journal = "European Physical Journal C. Particles and Fields",
issn = "1434-6044",
publisher = "Springer",
number = "4",

}

The ALICE Collaboration, Acharya, S, Brucken, EJ, Chang, B, Hilden, TE, Kim, DJ, Litichevskyi, V, Mieskolainen, MM, Orava, R, Parkkila, JE, Rak, J, Räsänen, SS, Saarinen, S, Slupecki, M, Snellman, TW, Trzaska, WH, Vargyas, M & Viinikainen, J 2019, 'Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at root S-NN=8.16 TeV', European Physical Journal C. Particles and Fields, vol. 79, no. 4, 307. https://doi.org/10.1140/epjc/s10052-019-6801-9

Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at root S-NN=8.16 TeV. / The ALICE Collaboration; Acharya, S.; Brucken, E. J.; Chang, B.; Hilden, T. E.; Kim, D. J.; Litichevskyi, V.; Mieskolainen, M. M.; Orava, R.; Parkkila, J. E.; Rak, J.; Räsänen, S. S.; Saarinen, S.; Slupecki, M.; Snellman, T. W.; Trzaska, W. H.; Vargyas, M.; Viinikainen, J.

In: European Physical Journal C. Particles and Fields, Vol. 79, No. 4, 307, 04.04.2019.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at root S-NN=8.16 TeV

AU - The ALICE Collaboration

AU - Acharya, S.

AU - Brucken, E. J.

AU - Chang, B.

AU - Hilden, T. E.

AU - Kim, D. J.

AU - Litichevskyi, V.

AU - Mieskolainen, M. M.

AU - Orava, R.

AU - Parkkila, J. E.

AU - Rak, J.

AU - Räsänen, S. S.

AU - Saarinen, S.

AU - Slupecki, M.

AU - Snellman, T. W.

AU - Trzaska, W. H.

AU - Vargyas, M.

AU - Viinikainen, J.

PY - 2019/4/4

Y1 - 2019/4/4

N2 - The pseudorapidity density of charged particles, dN(ch)/d eta, in p-Pb collisions has been measured at a centre of-mass energy per nucleon-nucleon pair of root S-NN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, vertical bar eta vertical bar < 1.8. The dN(ch)/d eta value is 19.1 +/- 0.7 at vertical bar eta vertical bar < 0.5. This quantity divided by < N-part >/2 is 4.73 +/- 0.20, where < N-part > is the average number of participating nucleons, is 9.5% higher than the corresponding value for p-Pb collisions at root S-NN = 5.02 TeV. Measurements are compared with models based on different mechanisms for particle production. All models agree within uncertainties with data in the Pb-going side, while HIJING overestimates, showing a symmetric behaviour, and EPOS underestimates the p-going side of the dN(ch)/d eta distribution. Saturation-based models reproduce the distributions well for eta > -1.3. The dN(ch)/d eta is also measured for different centrality estimators, based both on the charged particle multiplicity and on the energy deposited in the Zero Degree Calorimeters. A study of the implications of the large multiplicity fluctuations due to the small number of participants for systems like p-Pb in the centrality calculation for multiplicity-based estimators is discussed, demonstrating the advantages of determining the centrality with energy deposited near beam rapidity.

AB - The pseudorapidity density of charged particles, dN(ch)/d eta, in p-Pb collisions has been measured at a centre of-mass energy per nucleon-nucleon pair of root S-NN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, vertical bar eta vertical bar < 1.8. The dN(ch)/d eta value is 19.1 +/- 0.7 at vertical bar eta vertical bar < 0.5. This quantity divided by < N-part >/2 is 4.73 +/- 0.20, where < N-part > is the average number of participating nucleons, is 9.5% higher than the corresponding value for p-Pb collisions at root S-NN = 5.02 TeV. Measurements are compared with models based on different mechanisms for particle production. All models agree within uncertainties with data in the Pb-going side, while HIJING overestimates, showing a symmetric behaviour, and EPOS underestimates the p-going side of the dN(ch)/d eta distribution. Saturation-based models reproduce the distributions well for eta > -1.3. The dN(ch)/d eta is also measured for different centrality estimators, based both on the charged particle multiplicity and on the energy deposited in the Zero Degree Calorimeters. A study of the implications of the large multiplicity fluctuations due to the small number of participants for systems like p-Pb in the centrality calculation for multiplicity-based estimators is discussed, demonstrating the advantages of determining the centrality with energy deposited near beam rapidity.

KW - 114 Physical sciences

KW - AU COLLISIONS

KW - MULTIPLICITY

KW - DISTRIBUTIONS

KW - DEPENDENCE

KW - CENTRALITY

U2 - 10.1140/epjc/s10052-019-6801-9

DO - 10.1140/epjc/s10052-019-6801-9

M3 - Article

VL - 79

JO - European Physical Journal C. Particles and Fields

JF - European Physical Journal C. Particles and Fields

SN - 1434-6044

IS - 4

M1 - 307

ER -