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

Acharya, S, Acosta, FT, Adamova, D, Adhya, SP, Adler, A, Adolfsson, J, Aggarwal, MM, Rinella, G Aglieri, Agnello, M, Ahammed, Z
et al (show 1000 more authors) (2019) Charged-particle pseudorapidity density at mid-rapidity in p-Pb collisions at root S-NN=8.16 TeV. EUROPEAN PHYSICAL JOURNAL C, 79 (4). 307-.

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The pseudorapidity density of charged particles, d Nch/ 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 Nch/ d η value is 19.1 ± 0.7 at | η| < 0.5. This quantity divided by ⟨ Npart⟩ / 2 is 4.73 ± 0.20 , where ⟨ Npart⟩ 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 Nch/ d η distribution. Saturation-based models reproduce the distributions well for η> - 1.3. The d Nch/ 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.

Item Type: Article
Uncontrolled Keywords: 5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences, 7 Affordable and Clean Energy
Depositing User: Symplectic Admin
Date Deposited: 14 Aug 2019 09:55
Last Modified: 20 Jun 2024 18:59
DOI: 10.1140/epjc/s10052-019-6801-9
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