Speaker
Description
We discuss recent results on possible jet quenching in collisions of small
systems: in $pp$, $pA$ and oxygen-oxygen collisions. Calculations of the radiative and collisional parton energy loss are performed for the temperature dependent running QCD coupling. We use parametrization of $\alpha_s(Q,T)$ which has a plateau around $Q \sim \kappa T$ (it is motivated by the lattice calculation of the effective QCD coupling in the QGP). The parameter $\kappa$ has been fitted to the LHC data on the nuclear modification factor $R_{AA}$ in heavy ion collisions. Using the optimal $\kappa$ we perform calculations of $R_{pp}$, $R_{pPb}$, and $R_{AA}$ and $v_2$ for O+O collisions. We find that predictions for $R_{OO}$ may differ substantially for scenarios with and without mini-QGP formation in $pp$ collisions.
We show that the available data on $R_{pPb}$ may be consistent with the QGP formation in $pp$ and $pPb$ collisions. However, a scenario with the QGP formation only in $pPb$ collisions is excluded.
