Untriggered di-hadron correlations using 2.76 TeV Pb-Pb collisions in ALICE

We present measurements of untriggered di-hadron correlations as a function of mean $p_{\rm{T}}$ in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV at ALICE. The momentum evolution of untriggered data has been studied by increasing the lower $p_{\rm{T}}$ acceptance of both charged particles and within momentum windows. A smooth evolution of the correlation structures is observed. We further quantify the evolution of the contributing components by fitting a model function. The model function emphasizes possible initial state fluctuation contributions via the use of higher harmonics, $v_{n}$ (n = 2, 3, 4, 5). A remainder is modeled via an asymmetric 2D Gaussian to extract parameters of the long range $\Delta\eta$ correlations, referred to as the ``soft ridge.'' In order to model nonflow contributions (via a 2D Gaussian) Fourier harmonics [1] are shown with and without such a 2D Gaussian. Extracted harmonics parameters are compared with published ALICE flow results [2] and IP Glasma model predictions [3].\\[4pt] [1] A.M Adare et al.(ALICE Collaboration), Phys. Lett. B 708 (2012)\\[0pt] [2] K. Aamodt et al.(ALICE Collaboration), Phys. Rev. Lett. 107, 032301(2011)\\[0pt] [3] Prithwish Tribedy (private comm.)