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


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Acharya S., Acosta F., Adamová D., Adhya S., Adler A., Adolfsson J., ...Daha Fazla

European Physical Journal C, cilt.79, sa.4, 2019 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 79 Sayı: 4
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1140/epjc/s10052-019-6801-9
  • Dergi Adı: European Physical Journal C
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Yıldız Teknik Üniversitesi Adresli: Hayır

Özet

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.