In:
Journal of High Energy Physics, Springer Science and Business Media LLC, Vol. 2020, No. 9 ( 2020-09)
Abstract:
Measurement of Z-boson production in p-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 8 . 16 TeV and Pb-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 5 . 02 TeV is reported. It is performed in the dimuon decay channel, through the detection of muons with pseudorapidity − 4 〈 η μ 〈 − 2 . 5 and transverse momentum $$ {p}_{\mathrm{T}}^{\mu } $$ p T μ 〉 20 GeV/ c in the laboratory frame. The invariant yield and nuclear modification factor are measured for opposite-sign dimuons with invariant mass 60 〈 m μμ 〈 120 GeV/ c 2 and rapidity 2 . 5 〈 $$ {y}_{\mathrm{cms}}^{\mu \mu} $$ y cms μμ 〈 4. They are presented as a function of rapidity and, for the Pb-Pb collisions, of centrality as well. The results are compared with theoretical calculations, both with and without nuclear modifications to the Parton Distribution Functions (PDFs). In p-Pb collisions the center-of-mass frame is boosted with respect to the laboratory frame, and the measurements cover the backward ( − 4 . 46 〈 $$ {y}_{\mathrm{cms}}^{\mu \mu} $$ y cms μμ 〈 − 2 . 96) and forward (2 . 03 〈 $$ {y}_{\mathrm{cms}}^{\mu \mu} $$ y cms μμ 〈 3 . 53) rapidity regions. For the p-Pb collisions, the results are consistent within experimental and theoretical uncertainties with calculations that include both free-nucleon and nuclear-modified PDFs. For the Pb-Pb collisions, a 3 . 4 σ deviation is seen in the integrated yield between the data and calculations based on the free-nucleon PDFs, while good agreement is found once nuclear modifications are considered.
Type of Medium:
Online Resource
ISSN:
1029-8479
DOI:
10.1007/JHEP09(2020)076
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2020
detail.hit.zdb_id:
2027350-2
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