Azimuthal correlations of D-mesons in p+p and p+Pb collisions at LHC energies

. We study the correlations of D mesons produced in p+p and p+Pb collisions. These are found to be sensitive to the effects of the cold nuclear medium and the transverse momentum ( p T ) regions we are looking into. In order to put this on a quantitative footing, as a first step we analyse the azimuthal correlations of D meson-charged hadron (Dh), and then predict the same for D meson-anti D meson ( D D ̄ ) pairs in p+p and p+Pb collisions with strong coupling at leading order O ( α s 2 ) and next-to-leading order O ( α s 3 ) , which includes space-time evolution (in both systems) as well as cold nuclear matter effects (in p+Pb). This also sets the stage and baseline for the identification and study of medium modification of azimuthal correlations in relativistic collision of heavy nuclei at the Large Hadron Collider.