Heavy Flavor Kinematic Correlations in Cold Nuclear Matter

Abstract

It has been proposed that the azimuthal distributions of heavy flavor quark-antiquark pairs may be modified in the medium of a heavy-ion collision. This assumption was tested through next-to-leading order (NLO) calculations of the azimuthal distribution, $d\sigma/d\phi$, including transverse momentum broadening, employing $\langle k_T^2 \rangle$ and fragmentation in exclusive $Q \overline Q$ pair production. The results have been compared to $p+p$ and $p + \overline p$ data on $Q \overline Q$ azimuthal correlations as well as $b \overline b$ correlations in $p+p$ collisions through their decays to $J/\psi J/\psi$, as measured by LHCb. Agreement with the data was found to be excellent. Possible cold and hot matter effects on these correlations are investigated through the effects of nuclear modifications of the parton densities, enhanced $k_T$ broadening and energy loss.