We show that high-$p_{\perp }{R}_{\mathrm{AA}}$ and $v_2$ are sensitive to the early expansion dynamics, and that the high-$p_{\perp }$ observables prefer delayed onset of energy loss and transverse expansion. To calculate high-$p_{\perp }{R}_{\mathrm{AA}}$ and $v_2$, we employ our newly developed DREENA-A framework, which combines state-of-the-art dynamical energy loss model with (3$+$1)-dimensional hydrodynamical simulations. The model applies to both light and heavy flavor, and we predict a larger sensitivity of heavy flavor observables to the onset of transverse expansion. This presents the first time when bulk QGP behavior has been constrained by high-$p_{\perp }$ observables and related theory, i.e., by so-called QGP tomography.

• Received 19 August 2020
• Revised 24 July 2021
• Accepted 25 January 2022

DOI:https://doi.org/10.1103/PhysRevC.105.L021901