# Flow dominance and factorization of transverse momentum correlations in Pb--Pb collisions at the LHC

Submission Date:
06/02/2017
Article Information
Submission Form
System:
Pb-Pb
Energy:
2.76 TeV
Abstract Plain Text:

We present first measurement of charged particles differential transverse momentum correlation function, $\Delta p_{\rm T}\Delta p_{\rm T}$, in Pb--Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. The correlations are reported as a function of the relative pseudorapidity, $\Delta\eta$, and azimuthal angle difference, $\Delta\varphi$. The $\Delta\varphi$ dependence is found to be largely independent of $\Delta\eta$ at $\Delta\eta >$ 0.9. $\Delta p_{\rm T}\Delta p_{\rm T}exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations,$R_2$, previously reported. In 0-5\% most central Pb--Pb collisions the two particle transverse momentum correlation function exhibits a clear two hump structure at the “away-side”, an indication of the dominance of triangular flow. Detailed comparison of$R_2$and$\Delta p_{\rm T}\Delta p_{\rm T}correlation functions utilizing Fourier decomposition show that the $\Delta p_{\rm T}\Delta p_{\rm T}correlations at$\Delta\eta >\$ 0.9 can be well reproduced by the “flow ansatz”, assuming that all the correlations are dominated by the anisotropic flow.