Bottomonium production in pp and Pb+Pb collisions with ATLAS

Bottomonium, a bound state of a bottom quark and its antiquark, is an excellent probe of the hot and dense medium created in heavy-ion collisions at LHC. The ATLAS collaboration collected the large datasets of $\it{pp}$ and Pb+Pb collisions in 2017 and 2018 corresponding to integrated luminosities of 0.26 fb$^{−1}$ and 1.38 nb$^{−1}$ respectively, at a centre-of-mass energy per nucleon pair of 5.02 TeV. In this poster, bottomonium states are reconstructed via the dimuon decay channel in the rapidity range of $|y|<1$, and their production in PbPb collisions is compared to that in pp collisions to extract the nuclear modification factor, $R_{\mathrm{AA}}$, as a function of event centrality and transverse momentum. In addition, the relative suppression of the excited states $\varUpsilon\mathrm{(nS)}$ to the ground state $\varUpsilon\mathrm{(1S)}$ is studied.