The pseudorapidity density of charged particles, d Nch /dη, 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 dNch/dη 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 aver- age 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 dif- ferent 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 /dη dis- tribution. Saturation-based models reproduce the distribu- tions well for η > −1.3. The dNch/dη 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 partic- ipants for systems like p–Pb in the centrality calculation for multiplicity-based estimators is discussed, demonstrat- ing the advantages of determining the centrality with energy deposited near beam rapidity.

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

Barioglio L.;Beole S.;Bianchi L.;Botta E.;Ferretti A.;Gagliardi M.;Masera M.;Puccio M.;Trogolo S.;Vercellin E.;
2019-01-01

Abstract

The pseudorapidity density of charged particles, d Nch /dη, 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 dNch/dη 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 aver- age 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 dif- ferent 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 /dη dis- tribution. Saturation-based models reproduce the distribu- tions well for η > −1.3. The dNch/dη 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 partic- ipants for systems like p–Pb in the centrality calculation for multiplicity-based estimators is discussed, demonstrat- ing the advantages of determining the centrality with energy deposited near beam rapidity.
2019
79
4
307
307
http://link.springer-ny.com/link/service/journals/10052/index.htm
Acharya S.; Acosta F.-T.; Adamova D.; Adhya S.P.; Adler A.; Adolfsson J.; Aggarwal M.M.; Rinella G.A.; Agnello M.; Ahammed Z.; Ahmad S.; Ahn S.U.; Aio...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1710772
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