CERN Accelerating science

(Color online) (a) $P_2 (\Deta,\Dphi) $ in the 5\% most central Pb--Pb collisions. The region $|\Deta| < 0.15$ and $|\Delta\varphi| < 0.13$ rad, where the weight technique used in this analysis does not provide a reliable efficiency correction, is excluded. (b) $P_2 (\Dphi)$ for $|\Delta\eta| \geq 0.9$. Systematic errors are shown as gray boxes. Note the statistically significant dip at $\Delta\varphi \sim \pi$.

(Color online) (a) $P_2 (\Deta,\Dphi) $ in the 5\% most central Pb--Pb collisions. The region $|\Deta| < 0.15$ and $|\Delta\varphi| < 0.13$ rad, where the weight technique used in this analysis does not provide a reliable efficiency correction, is excluded. (b) $P_2 (\Dphi)$ for $|\Delta\eta| \geq 0.9$. Systematic errors are shown as gray boxes. Note the statistically significant dip at $\Delta\varphi \sim \pi$.

(Color online) $v_{n}$ coefficients where $n=2,3,4$ in the range (a) $0.2 \leq |\Delta\eta| \leq 0.9$ and (c) $0.9 \leq |\Delta\eta| \leq 1.9$ obtained from the $P_2$ correlation function. The coefficients are compared with the expectations from the flow ansatz calculated in their respective $\Deta$ ranges in Pb--Pb collisions. Statistical errors are shown as vertical solid lines, whereas systematic errors are displayed as colored bands. Ratios of the $v_{n}$ coefficients and their corresponding flow ansatz values are shown in (b) and (d). The errors on the ratios are only statistical.

(Color online) $v_{n}$ coefficients, $n=2, 3, 4$, obtained from (a) $P_2$ and (b) $R_2$ correlators, as a function of $|\Delta\eta|$ in the 5\% most central Pb -- Pb collisions. Statistical errors are shown as vertical solid lines whereas systematic uncertainties are displayed as shaded bands. Panels (c -- d): ratios of the $v_{n}$, $n=2, 3, 4$, by the corresponding values of $v_{n}$ measured at $\Delta\eta = 0.3$.