Measurement of $\Upsilon(1{\rm S})$ elliptic flow at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=5.02$ TeV

Understand

The first measurement of the $\Upsilon(1{\rm S})$ elliptic flow coefficient ($v_2$) is performed at forward rapidity (2.5 $<$ $y$ $<$ 4) in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE detector at the LHC.

• The results are obtained with the scalar product method and are reported as a function of transverse momentum ($p_{\rm{T}}$) up to 15 GeV/$c$ in the 5-60% centrality interval.
• The measured $\Upsilon(1{\rm S})$ $v_2$ is consistent with zero and with the small positive values predicted by transport models within uncertainties.
• The $v_2$ coefficient in 2 $<$ $p_{\rm T}$ $<$ 15 GeV/$c$ is lower than that of inclusive J/$\psi$ mesons in the same $p_{\rm{T}}$ interval by 2.6 standard deviations.