Two particle differential transverse momentum and number density correlations in p-Pb and Pb-Pb at the LHC

We present measurements of two-particle differential number correlation functions $R_2$ and transverse momentum correlation functions $P_2$, obtained from p-Pb collisions at 5.02 TeV and Pb-Pb collisions at 2.76 TeV. The results are obtained using charged particles in the pseudorapidity range $\mathrm{\mid }\eta \mathrm{\mid }<$ 1.0, and transverse momentum range $0.2<p_{\mathrm{T}}<2.0$ GeV/$c$ as a function of pair separation in pseudorapidity, $\mathrm{\mid }\mathrm{\Delta }\eta \mathrm{\mid }$, azimuthal angle, $\mathrm{\Delta }\phi$, and for several charged-particle multiplicity classes. Measurements are carried out for like-sign and unlike-sign charged-particle pairs separately and combined to obtain charge-independent and charge-dependent correlation functions. We study the evolution of the width of the near-side peak of these correlation functions with collision centrality. Additionally, we study Fourier decompositions of the correlators in $\mathrm{\Delta }\phi$ as a function of the pair separation $\mathrm{\mid }\mathrm{\Delta }\eta \mathrm{\mid }$. Significant differences in the dependence of their harmonic coefficients on multiplicity classes are found. These differences can be exploited, in theoretical models, to obtain further insight into charged-particle production and transport in heavy-ion collisions. Moreover, an upper limit of non-flow contributions to flow coefficients $v_n$ measured in Pb-Pb collisions based on the relative strength of Fourier coefficients measured in p-Pb interactions is estimated.