$\dNchdy$ distribution for the 5% most central Pb-Pb collisions. A Gaussian distribution has been fit to the data ($\sigma = 3.86$). A Landau-Carruthers Gaussian and a Landau-Wong function are also shown. The full drawn line shows a fit to the sum of two Gaussian distributions of equal widths with the means at $\eta = \pm 2.17$ and $\sigma = 2.6$ as its area reproduces the estimated total number of charged particles.
The inset shows the energy dependence of the ratio of $\sigma$ from a Gaussian fit to the expected Landau-Carruthers $\sigma$ extended to $\snn=2.76$ TeV along with including RHIC points derived from the $\dNchdeta$ distributions measured by BRAHMS and PHOBOS converted to $\dNchdy$ (the higher point and the lower point, respectively) using the same method employed at $\snn=2.76$ TeV.