Charged-particle pseudorapidity density at mid-rapidity in p–Pb collisions at √sNN = 8.16 TeV

ALICE Collaboration

Research output: Contribution to journalArticle

Abstract

The pseudorapidity density of charged particles, d N ch / d η, in p–Pb collisions has been measured at a centre-of-mass energy per nucleon–nucleon pair of sNN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, | η| < 1.8. The d N ch / d η value is 19.1 ± 0.7 at | η| < 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 sNN = 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 d N ch / d η distribution. Saturation-based models reproduce the distributions well for η> - 1.3. The d N ch / d η 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 (US)
Article number307
JournalEuropean Physical Journal C
Volume79
Issue number4
DOIs
StatePublished - Apr 1 2019

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Charged particles
charged particles
estimators
collisions
Calorimeters
calorimeters
center of mass
energy

All Science Journal Classification (ASJC) codes

  • Engineering (miscellaneous)
  • Physics and Astronomy (miscellaneous)

Cite this

Charged-particle pseudorapidity density at mid-rapidity in p–Pb collisions at √sNN = 8.16 TeV. / ALICE Collaboration.

In: European Physical Journal C, Vol. 79, No. 4, 307, 01.04.2019.

Research output: Contribution to journalArticle

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title = "Charged-particle pseudorapidity density at mid-rapidity in p–Pb collisions at √sNN = 8.16 TeV",
abstract = "The pseudorapidity density of charged particles, d N ch / d η, in p–Pb collisions has been measured at a centre-of-mass energy per nucleon–nucleon pair of sNN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, | η| < 1.8. The d N ch / d η value is 19.1 ± 0.7 at | η| < 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 sNN = 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 d N ch / d η distribution. Saturation-based models reproduce the distributions well for η> - 1.3. The d N ch / d η 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.",
author = "{ALICE Collaboration} and S. Acharya and Acosta, {F. T.} and D. Adamov{\'a} and Adhya, {S. P.} and A. Adler and J. Adolfsson and Aggarwal, {M. M.} and Rinella, {G. Aglieri} and M. Agnello and Z. Ahammed and S. Ahmad and Ahn, {S. U.} and S. Aiola and A. Akindinov and M. Al-Turany and Alam, {S. N.} and Albuquerque, {D. S.D.} and D. Aleksandrov and B. Alessandro and Alfanda, {H. M.} and Molina, {R. Alfaro} and Y. Ali and A. Alici and A. Alkin and J. Alme and T. Alt and L. Altenkamper and I. Altsybeev and Anaam, {M. N.} and C. Andrei and D. Andreou and Andrews, {H. A.} and A. Andronic and M. Angeletti and V. Anguelov and C. Anson and T. Antičić and F. Antinori and P. Antonioli and R. Anwar and N. Apadula and L. Aphecetche and H. Appelsh{\"a}user and S. Arcelli and R. Arnaldi and M. Arratia and Arsene, {I. C.} and M. Arslandok and A. Augustinus and Seger, {Janet E.}",
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T1 - Charged-particle pseudorapidity density at mid-rapidity in p–Pb collisions at √sNN = 8.16 TeV

AU - ALICE Collaboration

AU - Acharya, S.

AU - Acosta, F. T.

AU - Adamová, D.

AU - Adhya, S. P.

AU - Adler, A.

AU - Adolfsson, J.

AU - Aggarwal, M. M.

AU - Rinella, G. Aglieri

AU - Agnello, M.

AU - Ahammed, Z.

AU - Ahmad, S.

AU - Ahn, S. U.

AU - Aiola, S.

AU - Akindinov, A.

AU - Al-Turany, M.

AU - Alam, S. N.

AU - Albuquerque, D. S.D.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alfanda, H. M.

AU - Molina, R. Alfaro

AU - Ali, Y.

AU - Alici, A.

AU - Alkin, A.

AU - Alme, J.

AU - Alt, T.

AU - Altenkamper, L.

AU - Altsybeev, I.

AU - Anaam, M. N.

AU - Andrei, C.

AU - Andreou, D.

AU - Andrews, H. A.

AU - Andronic, A.

AU - Angeletti, M.

AU - Anguelov, V.

AU - Anson, C.

AU - Antičić, T.

AU - Antinori, F.

AU - Antonioli, P.

AU - Anwar, R.

AU - Apadula, N.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arcelli, S.

AU - Arnaldi, R.

AU - Arratia, M.

AU - Arsene, I. C.

AU - Arslandok, M.

AU - Augustinus, A.

AU - Seger, Janet E.

PY - 2019/4/1

Y1 - 2019/4/1

N2 - The pseudorapidity density of charged particles, d N ch / d η, in p–Pb collisions has been measured at a centre-of-mass energy per nucleon–nucleon pair of sNN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, | η| < 1.8. The d N ch / d η value is 19.1 ± 0.7 at | η| < 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 sNN = 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 d N ch / d η distribution. Saturation-based models reproduce the distributions well for η> - 1.3. The d N ch / d η 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, d N ch / d η, in p–Pb collisions has been measured at a centre-of-mass energy per nucleon–nucleon pair of sNN = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, | η| < 1.8. The d N ch / d η value is 19.1 ± 0.7 at | η| < 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 sNN = 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 d N ch / d η distribution. Saturation-based models reproduce the distributions well for η> - 1.3. The d N ch / d η 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.

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

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

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JO - Zeitschrift fur Physik C-Particles and Fields

JF - Zeitschrift fur Physik C-Particles and Fields

SN - 1434-6044

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