Measurement of the elliptic flow of $\Upsilon\textrm{(1S)}$ and $\Upsilon\textrm{(2S)}$ mesons in PbPb collisions at $\sqrt{\mathrm{s_{NN}}}=5.02~\mathrm{TeV}$

The second-order Fourier coefficients ($v_{2}$) characterizing the azimuthal dependence of $\Upsilon\textrm{(1S)}$ and $\Upsilon\textrm{(2S)}$ mesons arising from PbPb collisions at $\sqrt{\mathrm{s_{NN}}}=5.02~\mathrm{TeV}$ are determined. The $\Upsilon$ mesons are reconstructed using the di-muon decay channel as measured using the CMS detector. The dataset was obtained in 2018 and corresponds to an integrated luminosity of 1.7 $\mathrm{nb^{-1}}$. The scalar product method is used for the $v_{2}$ analysis. Results are reported for the rapidity range $|y| < 2.4$, with $0 < p_{\mathrm{T}} < 50~\mathrm{GeV}$, and in four centrality classes of 0-$10\%$, 10-$30\%$, 30-$50\%$ and 50-$90\%$, with 0-$10\%$ corresponding to the most central collisions. The average $v_{2}$ value for $\Upsilon\textrm{(1S)}$ mesons is 0.007 $\pm$ 0.011 (stat) $\pm$ 0.005 (syst) in the 10-$90\%$ centrality interval. The observed $v_{2}$ values are consistent with zero for all $p_{\mathrm{T}}$ and centrality ranges, with a maximum offset of 2.5 standard deviations. The $v_{2}$ value for $\Upsilon\textrm{(2S)}$ mesons is measured for the first time and found to be -0.063 $\pm$ 0.085 (stat) $\pm$ 0.037 (syst) in the 10-$90\%$ centrality interval.