NPA Seminar: Mike Sas, Utrecht University/Nikhef, “Probing small and large collision systems using photons: from particle production in pp collisions to measuring the space-time evolution of the Quark Gluon Plasma in AA collisions”

Direct photons and neutral mesons produced in AA collisions probe the physics of the Quark-Gluon Plasma (QGP), which is formed in heavy-ion collisions. The direct photons contain information about the temperature and space-time evolution of the QGP, while the neutral meson production gives interesting insights into particle production mechanisms in all collisions systems.
In the ALICE experiment, photons are reconstructed using the calorimeters or via conversions in the detector material. Combining the excellent momentum resolution of the conversion photons and the high reconstruction efficiency and triggering capability of calorimeters at higher momentum, ALICE is able to measure photons and light neutral mesons over a wide kinematic range.
Combining state-of-the-art reconstruction techniques with the high statistics delivered by the LHC in Run 2 gives us the opportunity to enhance the precision of our measurements and perform even more differential studies. In this seminar, the latest results on neutral meson production across different system sizes will be presented, together with an overview of the most recent direct photon measurements in heavy-ion collisions.
Host: Helen Caines