Charged-particle pseudorapidity density at mid-rapidity in p–Pb collisions at $$\pmb {\sqrt{s_{\scriptscriptstyle {\mathrm{NN}}}}}$$ = 8.16 TeV
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 $$\sqrt{s_{NN}}$$ = 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 (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 $$\sqrt{s_{NN}}$$ = 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 d$$N$$ch/d$$η$$ distribution. Saturation-based models reproduce the distributions well for < -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.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
- Contributing Organization:
- ALICE Collaboration
- Grant/Contract Number:
- AC02-05CH11231; AC05-00OR22725
- OSTI ID:
- 1546662
- Journal Information:
- European Physical Journal. C, Particles and Fields, Journal Name: European Physical Journal. C, Particles and Fields Journal Issue: 4 Vol. 79; ISSN 1434-6044
- Publisher:
- SpringerCopyright Statement
- Country of Publication:
- United States
- Language:
- English
One-dimensional charged kaon femtoscopy in p -Pb collisions at s NN = 5.02 TeV
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journal | August 2019 |
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