A measurement of the production of vector bottomonium states, $\Upsilon \left(\text{1S}\right)$, $\Upsilon \left(\text{2S}\right)$, and $\Upsilon \left(\text{3S}\right)$, in $\mathrm{Pb}+\mathrm{Pb}$ and $pp$ collisions at a center-of-mass energy per nucleon pair of 5.02 TeV is presented. The data correspond to integrated luminosities of $1.38{\text{nb}}^{-1}$ of $\mathrm{Pb}+\mathrm{Pb}$ data collected in 2018, $0.44{\text{nb}}^{-1}$ of $\mathrm{Pb}+\mathrm{Pb}$ data collected in 2015, and $0.26{\text{fb}}^{-1}$ of $pp$ data collected in 2017 by the ATLAS detector at the Large Hadron Collider. The measurements are performed in the dimuon decay channel for transverse momentum $p_{\text{T}}^{\mu \mu }<30\mathrm{GeV}$, absolute rapidity $|y^{\mu \mu }|<1.5$, and $\mathrm{Pb}+\mathrm{Pb}$ event centrality 0–80%. The production rates of the three bottomonium states in $\mathrm{Pb}+\mathrm{Pb}$ collisions are compared with those in $pp$ collisions to extract the nuclear modification factors as functions of event centrality, $p_{\text{T}}^{\mu \mu }$, and $|y^{\mu \mu }|$. In addition, the suppression of the excited states relative to the ground state is studied. The results are compared with theoretical model calculations.

• Received 9 May 2022
• Accepted 24 October 2022

DOI:https://doi.org/10.1103/PhysRevC.107.054912

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