Azimuthal anisotropy of charged particles with transverse momentum up to 100 GeV/c in PbPb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\text{TeV}$

The Fourier coefficients $v_2$ and $v_3$ characterizing the anisotropy of the azimuthal distribution of charged particles produced in PbPb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\text{TeV}$ are measured with data collected by the CMS experiment. The measurements cover a broad transverse momentum range, $1<p_{\mathrm{T}}<100\text{GeV}/c$. The analysis focuses on the $p_{\mathrm{T}}>10\text{GeV}/c$ range, where anisotropic azimuthal distributions should reflect the path-length dependence of parton energy loss in the created medium. Results are presented in several bins of PbPb collision centrality, spanning the 60% most central events. The $v_2$ coefficient is measured with the scalar product and the multiparticle cumulant methods, which have different sensitivities to initial-state fluctuations. The values from both methods remain positive up to $p_{\mathrm{T}}\sim 60\text{–}80\text{GeV}/c$, in all examined centrality classes. The $v_3$ coefficient, only measured with the scalar product method, tends to zero for $p_{\mathrm{T}}\gtrsim 20\text{GeV}/c$. Comparisons between theoretical calculations and data provide new constraints on the path-length dependence of parton energy loss in heavy ion collisions and highlight the importance of the initial-state fluctuations.