Experimental characterizations of partonic energy loss in heavy ion collisions

by Jeffrey Ouellette (University of Colorado Boulder (US))

Wednesday 16 Jun 2021, 13:00 → 14:00 US/Eastern

Obtaining a complete description of the Quark-Gluon Plasma (QGP) droplets created in collisions between large nuclei requires a clear picture of how partons emerging from hard scattering events interact with and traverse the plasma. Large heavy ion collision datasets following run 2 at the LHC are enabling such measurements in previously difficult-to-reach kinematic regimes, particularly with rare electroweak probes. New measurements by ATLAS of Z boson-hadron correlations in proton-proton and lead-lead collisions will be presented and discussed. The Z boson is colorless to the QGP, offering the unique benefit of controlling for the parton properties prior to any final state energy loss. Extending this technique to small collision systems such as proton-lead, or to possible novel systems in run 3, could provide additional constraints on final state effects in small collision systems, as well as new information on initial state modification. In the future, the sPHENIX detector at RHIC will be able to perform similar photon-tagged measurements at lower energies, providing powerful constraints on the thermodynamics of hot nuclear matter.